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Author Ghali, Mohsen; Ohtani1, Keita; Ohno, Yuzo; Ohno, Hideo
Title Generation and control of polarization-entangled photons from GaAs island quantum dots by an electric field Type Journal Article
Year 2012 Publication Nature Communications Abbreviated Journal Nat. Comm.
Volume 3 Issue 661 Pages (down) 6
Keywords fromIPMRAS
Abstract Semiconductor quantum dots are potential sources for generating polarization-entangled photons efficiently. The main prerequisite for such generation based on biexciton-exciton cascaded emission is to control the exciton fine-structure splitting. Among various techniques investigated for this purpose, an electric field is a promising means to facilitate the integration into optoelectronic devices. Here we demonstrate the generation of polarization-entangled photons from single GaAs quantum dots by an electric field. In contrast to previous studies, which were limited to In(Ga)As quantum dots, GaAs island quantum dots formed by a thickness fluctuation were used because they exhibit a larger oscillator strength and emit light with a shorter wavelength. A forward voltage was applied to a Schottky diode to control the fine-structure splitting. We observed a decrease and suppression in the fine-structure splitting of the studied single quantum dot with the field, which enabled us to generate polarization-entangled photons with a high fidelity of 0.72 ± 0.05.
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Notes Approved no
Call Number RPLAB @ gujma @ Serial 769
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Author Grotz, Bernhard; Hauf, Moritz V.; Dankerl, Markus; Naydenov, Boris; Pezzagna, Sébastien; Meijer, Jan; Jelezko, Fedor; Wrachtrup, Jörg; Stutzmann, Martin; Reinhard, Friedemann; Garrido, Jose A.
Title Charge state manipulation of qubits in diamond Type Journal Article
Year 2012 Publication Nature Communications Abbreviated Journal Nat. Comm.
Volume 3 Issue 729 Pages (down) 6
Keywords fromIPMRAS
Abstract The nitrogen-vacancy (NV) centre in diamond is a promising candidate for a solid-state qubit. However, its charge state is known to be unstable, discharging from the qubit state NV- into the neutral state NV0 under various circumstances. Here we demonstrate that the charge state can be controlled by an electrolytic gate electrode. This way, single centres can be switched from an unknown non-fluorescent state into the neutral charge state NV0, and the population of an ensemble of centres can be shifted from NV0 to NV-. Numerical simulations confirm the manipulation of the charge state to be induced by the gate-controlled shift of the Fermi level at the diamond surface. This result opens the way to a dynamic control of transitions between charge states and to explore hitherto inaccessible states, such as NV+.
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Publisher Place of Publication Editor
Language Summary Language Original Title
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Notes Approved no
Call Number RPLAB @ gujma @ Serial 770
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Author Minaeva, O.; Fraine, A.; Korneev, A.; Divochiy, A.; Goltsman, G.; Sergienko, A.
Title High resolution optical time-domain reflectometry using superconducting single-photon detectors Type Conference Article
Year 2012 Publication Frontiers in Opt. 2012/Laser Sci. XXVIII Abbreviated Journal Frontiers in Opt. 2012/Laser Sci. XXVIII
Volume Issue Pages (down) Fw3a.39
Keywords SSPD, SNSPD, Photodetectors; Fiber characterization; Light beams; Optical time domain reflectometry; Photon counting; Single mode fibers; Single photon detectors; Superconductors
Abstract We discuss the advantages and limitations of single-photon optical time-domain reflectometry with superconducting single-photon detectors. The higher two-point resolution can be achieved due to superior timing performance of SSPDs in comparison with InGaAs APDs.
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Corporate Author Thesis
Publisher Optical Society of America Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1237
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Author Pütz, P.; Honingh, C. E.; Jacobs, K.; Justen, M.; Schultz, M.; Stutzki, J.
Title Terahertz hot electron bolometer waveguide mixers for GREAT Type Journal Article
Year 2012 Publication Astron. Astrophys. Abbreviated Journal A&A
Volume 542 Issue Pages (down) L2
Keywords HEB mixer, applications
Abstract Context. Supplementing the publications based on the first-light observations with the German REceiver for Astronomy at Terahertz frequencies (GREAT) on SOFIA, we present background information on the underlying heterodyne detector technology. This Letter complements the GREAT instrument Letter and focuses on the mixers itself.

Aims. We describe the superconducting hot electron bolometer (HEB) detectors that are used as frequency mixers in the L1 (1400 GHz), L2 (1900 GHz), and M (2500 GHz) channels of GREAT. Measured performance of the detectors is presented and background information on their operation in GREAT is given.

Methods. Our mixer units are waveguide-based and couple to free-space radiation via a feedhorn antenna. The HEB mixers are designed, fabricated, characterized, and flight-qualified in-house. We are able to use the full intermediate frequency bandwidth of the mixers using silicon-germanium multi-octave cryogenic low-noise amplifiers with very low input return loss.

Results. Superconducting HEB mixers have proven to be practical and sensitive detectors for high-resolution THz frequency spectroscopy on SOFIA. We show that our niobium-titanium-nitride (NbTiN) material HEBs on silicon nitride (SiN) membrane substrates have an intermediate frequency (IF) noise roll-off frequency above 2.8 GHz, which does not limit the current receiver IF bandwidth. Our mixer technology development efforts culminate in the first successful operation of a waveguide-based HEB mixer at 2.5 THz and deployment for radioastronomy. A significant contribution to the success of GREAT is made by technological development, thorough characterization and performance optimization of the mixer and its IF interface for receiver operation on SOFIA. In particular, the development of an optimized mixer IF interface contributes to the low passband ripple and excellent stability, which GREAT demonstrated during its initial successful astronomical observation runs.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
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Area Expedition Conference
Notes Approved no
Call Number Serial 907
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Author Pernice, W.; Schuck, C.; Minaeva, O.; Li, M.; Goltsman, G. N.; Sergienko, A. V.; Tang, H. X.
Title High speed and high efficiency travelling wave single-photon detectors embedded in nanophotonic circuits Type Miscellaneous
Year 2012 Publication arXiv Abbreviated Journal arXiv
Volume 1108.5299 Issue Pages (down) 1-23
Keywords optical waveguides, waveguide SSPD, guantum photonics, jitter, detection efficiency
Abstract Ultrafast, high quantum efficiency single photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. High photon detection efficiency is essential for scalable measurement-based quantum computation, quantum key distribution, and loophole-free Bell experiments. However, imperfect modal matching and finite photon absorption rates have usually limited the maximum attainable detection efficiency of single photon detectors. Here we demonstrate a superconducting nanowire detector atop nanophotonic waveguides which allows us to drastically increase the absorption length for incoming photons. When operating the detectors close to the critical current we achieve high on-chip single photon detection efficiency up to 91% at telecom wavelengths, with uncertainty dictated by the variation of the waveguide photon flux. We also observe remarkably low dark count rates without significant compromise of detection efficiency. Furthermore, our detectors are fully embedded in a scalable silicon photonic circuit and provide ultrashort timing jitter of 18ps. Exploiting this high temporal resolution we demonstrate ballistic photon transport in silicon ring resonators. The direct implementation of such a detector with high quantum efficiency, high detection speed and low jitter time on chip overcomes a major barrier in integrated quantum photonics.
Address
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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Area Expedition Conference
Notes Approved no
Call Number Serial 845
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Author Shurakov, Alexander; Tong, Edward; Blundell, Raymond; Gol'tsman, Gregory
Title Microwave stabilization of HEB mixer by a microchip controller Type Conference Article
Year 2012 Publication IEEE MTT-S international microwave symposium digest Abbreviated Journal
Volume Issue Pages (down) 1-3
Keywords HEB mixer stability, microwave injection, Allan variance, Allan time
Abstract The stability of a Hot Electron Bolometer (HEB) mixer can be improved by the use of microwave injection. In this article we report a refinement of this approach. We introduce a microchip controller to facilitate the implementation of the stabilization scheme, and demonstrate that the feedback loop effectively suppresses drifts in the HEB bias current, leading to an improvement in the receiver stability. The measured Allan time of the mixer's IF output power is increased to > 10 s.
Address Montreal, QC, Canada
Corporate Author Thesis
Publisher Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
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Area Expedition Conference
Notes Approved no
Call Number Serial 857
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Author Казаков, А. Ю.; Кардакова, А. И.; Селиверстов, С. В.; Горшков, К. Н.; Дивочий, А. В.; Финкель, М. И.; Корнеев, А. А.; Вахтомин, Ю. Б.
Title Возможность применения сверхпроводниковых материалов в качестве отражающего покрытия холодного зеркала телескопа субмиллиметрового диапазона Type Journal Article
Year 2012 Publication Совр. проб. науки и обр. Abbreviated Journal Совр. проб. науки и обр.
Volume Issue 3 Pages (down) 1-5
Keywords radio telescope, superconducting coating
Abstract
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 2070-7428 ISBN Medium
Area Expedition Conference
Notes УДК 520.272.2 Approved no
Call Number RPLAB @ sasha @ казаковвозможность Serial 1030
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Author Beck, Matthias; Leiderer, Paul; Kabanov, Viktor V.; Gol'tsman, Gregory; Helm, Manfred; Demsar, Jure
Title Energy-gap dynamics of a superconductor NbN studied by time-resolved terahertz spectroscopy Type Abstract
Year 2012 Publication INIS Abbreviated Journal INIS
Volume 45 Issue 12 Pages (down) 1-3
Keywords NbN energy gap
Abstract Using time-resolved terahertz (THz) spectroscopy we performed direct studies of the photoinduced suppression and recovery of the SC gap in a conventional SC NbN. Both processes are found to be strongly temperature and excitation density dependent. The analysis of the data with the established phenomenological Rothwarf-Taylor model enabled us to determine the important microscopic constants: the Cooper pair-breaking rate via phonon absorption and the bare quasiparticle recombination rate. From the latter we were able to extract the dimensionless electron-phonon coupling constant, λ=1.1±0.1, in excellent agreement with theoretical estimates. The technique also allowed us to determine the absorbed energy required to suppress SC, which in NbN equals the thermodynamic condensation energy (in cuprates the two differ by an order of magnitude). Finally, we present the first studies of dynamics following resonant excitation with intense narrow band THz pulses tuned to above and below the superconducting gap. These suggest an additional process, particularly pronounced near Tc, that could be attributed to amplification of SC via effective quasiparticle cooling.
Address
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Publisher Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1383
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Author Henrich, D.; Dorner,S.; Hofherr, M.; Il'in, K.; Semenov, A.; Heintze, E.; Scheffler, M.; Dressel, M.; Siegel, M.
Title Broadening of hot-spot response spectrum of superconducting NbN nanowire single-photon detector with reduced nitrogen content Type Journal Article
Year 2012 Publication Abbreviated Journal J. Appl. Phys.
Volume 112 Issue Pages (down)
Keywords SSPD, SNSPD, magnetron sputtering, spectrum, NbN film, nitrogen concentration
Abstract The spectral detection efficiency and the dark count rate of superconducting nanowire

single-photon detectors (SNSPD) have been studied systematically on detectors made from thin

NbN films with different chemical compositions. Reduction of the nitrogen content in the 4 nm

thick NbN films results in a decrease of the dark count rates more than two orders of magnitude

and in a red shift of the cut-off wavelength of the hot-spot SNSPD response. The observed

phenomena are explained by an improvement of uniformity of NbN films that has been confirmed

by a decrease of resistivity and an increase of the ratio of the measured critical current to the

depairing current. The latter factor is considered as the most crucial for both the cut-off

wavelength and the dark count rates of SNSPD. Based on our results we propose a set of criteria

for material properties to optimize SNSPD in the infrared spectral region. VC 2012 American

Institute of Physics. [http://dx.doi.org/10.1063/1.4757625]
Address
Corporate Author D. Henrich, S. Dorner, M. Hofherr, K. Il'in, A. Semenov, E. Heintze, M. Scheffler, M. Dressel, M. Siegel Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title Broadening of hot-spot response spectrum of superconducting NbN nanowire single-photon detector with reduced nitrogen content
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number RPLAB @ seleznev @ Serial 877
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Author Inderbitzin, K.; Engel, A.; Schilling, A.; Il'in, K.; Siegel, M.
Title An ultra-fast superconducting Nb nanowire single-photon detector for soft x-rays Type Journal Article
Year 2012 Publication Abbreviated Journal Appl. Phys. Lett.
Volume 101 Issue Pages (down)
Keywords SSPD, SNSPD, x-ray, Nb
Abstract Although superconducting nanowire single-photon detectors (SNSPDs) are well studied regarding the

detection of infrared/optical photons and keV-molecules, no studies on continuous x-ray photon

counting by thick-film detectors have been reported so far. We fabricated a 100 nm thick niobium

x-ray SNSPD (an X-SNSPD) and studied its detection capability of photons with keV-energies in

continuous mode. The detector is capable to detect photons even at reduced bias currents of 0.4%,

which is in sharp contrast to optical thin-film SNSPDs. No dark counts were recorded in extended

measurement periods. Strikingly, the signal amplitude distribution depends significantly on the photon

energy spectrum.VC
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Publisher Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
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Notes Approved no
Call Number RPLAB @ seleznev @ Serial 878
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Author D. Henrich, L. Rehm S. Dörner, M. Hofherr, K. Il'in, A. Semenov, and M. Siegel
Title Detection efficiency of a spiral-nanowire superconducting single-photon detector Type Journal Article
Year 2012 Publication Abbreviated Journal
Volume Issue Pages (down)
Keywords Critical current, Nanoscale devices, Superconducting photodetectors.
Abstract We investigate the detection efficiency of a spiral layout of a Superconducting Nanowire Single-Photon Detector (SNSPD). The design is less susceptible to the critical current reduction in sharp turns of the nanowire than the conventional meander design. Detector samples with different nanowire width from 300 to 100 nm are patterned from a 4 nm thick NbN film deposited on sapphire substrates. The critical current IC at 4.2 K for spiral, meander, and simple bridge structures is measured and compared. On the 100 nm wide samples, the detection efficiency is measured in the wavelength range 400-1700 nm and the cut-off wavelength of the hot-spot plateau is determined. In the optical range, the spiral detector reaches a detection efficiency of 27.6%, which is ~1.5 times the value of the meander. In the infrared range the detection efficiency is more than doubled.
Address
Corporate Author D. Henrich, L. Rehm S. Dörner, M. Hofherr, K. Il'in, A. Semenov, and M. Siegel 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 RPLAB @ seleznev @ Serial 880
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Author Julia Toussaint, Roman Grüner, Marco Schubert, Torsten May, Hans-Georg Meyer, Benjamin Dietzek, Jürgen Popp, Matthias Hofherr, Matthias Arndt, Dagmar Henrich, Konstantin Il'in, and Michael Siegel
Title Superconducting single-photon counting system for optical experiments requiring time-resolution in the picosecond range Type Journal Article
Year 2012 Publication Abbreviated Journal AIP REVIEW OF SCIENTIFIC INSTRUMENTS
Volume 83 Issue Pages (down)
Keywords SSPD, picosecond, time-resolution
Abstract We have developed a cryogenic measurement system for single-photon counting, which can be used

in optical experiments requiring high time resolution in the picosecond range. The system utilizes

niobium nitride superconducting nanowire single-photon detectors which are integrated in a timecorrelated

single-photon counting (TCSPC) setup. In this work, we describe details of the mechanical

design, the electrical setup, and the cryogenic optical components. The performance of the complete

system in TCSPC mode is tentatively benchmarked using 140 fs long laser pulses at a repetition

frequency of 75MHz. Due to the high temporal stability of these pulses, the measured time resolution

of 35 ps (FWHM) is limited by the timing jitter of the measurement system. The result was crosschecked

in a Coherent Anti-stokes Raman Scattering (CARS) setup, where scattered pulses from a

β-barium borate crystal have been detected with the same time resolution.
Address
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Series Editor Series Title Abbreviated Series Title
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Notes Approved no
Call Number RPLAB @ seleznev @ Serial 885
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Author Чулкова, Г. М.; Корнеев, А. А.; Смирнов, К. В.; Окунев, О. В.
Title Энергетическая релаксация в примесных металлах, двумерном электронном газе в AlGaAs-GaAs, сверхпроводниковых пленках NbN и детекторы субмиллиметрового и ик излучения на их основе Type Book Whole
Year 2012 Publication Abbreviated Journal
Volume Issue Pages (down)
Keywords 2DEG, AlGaAs/GaAs, NbN detectors
Abstract Монография посвящена обзору исследований влияния эффектов электронного беспорядка на электронное взаимодействие в металлах, сверхпроводниках, полупроводниках, а также в различных низкоразмерных структурах. Актуальность поднятых в монографии вопросов определяется интенсивным развитием нанотехнологий, созданием новых наноструктурированных материалов и уникальных наноэлементов для электроники и фотоники. Упругое электронное рассеяние на границах наноструктур качественно меняет взаимодействие электронов с фонолами, что, безусловно, должно учитываться при проектировании соответствующей элементной базы. Прикладная часть работы посвящена контролируемой модификации электронных процессов для оптимизации новых наносенсоров на основе электронного разогрева в сверхпроводниковых и полупроводниковых структурах. Монография предназначена для студентов старших курсов, аспирантов и начинающих следователей, работающих в области сверхпроводниковой наноэлектроники.
Address Москва
Corporate Author Thesis
Publisher Прометей, МПГУ Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 978-5-4263-0118-4 Medium
Area Expedition Conference
Notes УДК: 537.311 Approved no
Call Number Serial 1818
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Author Семенов, А. В.; Корнеев, А. А.; Лобанов, Ю. В.; Корнеева, Ю. П.; Рябчун, С. А.; Лаврова, О. С.; Третьяков, И. В.; Флоря, И. Н.; Силаев, М. А.; Кинев, Н. В.; Ковалюк, В. В.; Смирнов, К. В.; Гольцман, Г. Н.
Title Поляризация электромагнитной волны вблизи фокуса зеркала и системы зеркал в субтерагерцовом диапазоне частот Type Journal Article
Year 2012 Publication Современные проблемы науки и образования Abbreviated Journal
Volume Issue 2 Pages (down)
Keywords sub-terahertz radio telescope
Abstract Рассмотрено влияние оптической системы телескопа на поляризацию принимаемого электромагнитного сигнала. Описано изменение поляризации луча при отражении от произвольно ориентированной поверхности зеркала. Учтены искажения поляризации, обусловленные как отклонением лучей от первоначального направления, так и различием в коэффициентах отражения для разных поляризаций в случае неидеального отражения. В рамках метода Френеля получены оценочные формулы, дающие отношение амплитуд поля с исходной поляризацией и с поляризацией, перпендикулярной исходной, вблизи фокальной точки оптической системы. Формулы выведены для нескольких практически важных случаев, в том числе для параболического зеркала и системы двух зеркал. Оценена верхняя граница поляризационных искажений в пределах кружка Эйри. Полученные оценки согласуются с результатами численного расчёта для двухзеркального радиотелескопа субтерагерцового диапазона.
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Language Russian Summary Language Original Title
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Notes 9 страниц; УДК 535-47 Approved no
Call Number Serial 1819
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Author Semenov, A. V.; Devyatov, I. A.; Korneev, A. A.; Smirnov, K. V.; Goltsman, G. N.; Melnikov, A. P.
Title Derivation of expression for thermodynamic potential of “dirty” superconductor Type Journal Article
Year 2012 Publication Rus. J. Radio Electron. Abbreviated Journal Rus. J. Radio Electron.
Volume Issue 4 Pages (down)
Keywords dirty superconductor, Usadel theory, thermodynamic potential
Abstract We derive a formula for thermodynamic potential of dirty superconductor which express it via isotropic quasiclassical Green functions of Usadel theory. Our result allows unify description of dynamic processes and fluctuations in superconducting nano-electronic devices.
Address
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Language Russian Summary Language Original Title
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Notes 7 pages Approved no
Call Number Serial 1824
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