Nanjing University of Posts and Telecommunications
Nanjing, China

Nanjing University of Posts and Telecommunications is a public university in Nanjing, Jiangsu province, China.Nanjing University of Posts and Telecommunications is a key provincial university established by Jiangsu Provincial People’s Government and the former Ministry of Information Industry. Owing to its history, the university has been characteristic of high quality graduates with reputations. With information technology and telecommunications as its main features, it offers a wide range of subjects including science, engineering, economics, management, arts and education, most of which are related to applied science and engineering. NUPT has been making efforts to construct harmony-based disciplines upon different levels, running undergraduate, master and Ph.D. programs. Wikipedia.

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Zou Y.,Nanjing University of Posts and Telecommunications
IEEE Transactions on Wireless Communications | Year: 2017

In this paper, we examine the physical-layer security for a spectrum sharing system consisting of multiple source-destination pairs, which dynamically access their shared spectrum for data transmissions in the presence of an eavesdropper. We propose a source cooperation (SC) aided opportunistic jamming framework for protecting the transmission confidentiality of the spectrum sharing system against eavesdropping. Specifically, when a source node is allowed to access the shared spectrum for data transmissions, another source is opportunistically selected in the spectrum sharing system to transmit an artificial noise for disrupting the eavesdropper without affecting the legitimate transmissions. We present two specific SC aided opportunistic jamming schemes, namely the SC aided random jammer selection (RJS) and optimal jammer selection (OJS), which are referred to as the SC-RJS and SC-OJS, respectively. We also consider the conventional non-cooperation as a baseline. We derive closed-form intercept probability expressions for the non-cooperation, SC-RJS and SC-OJS schemes, based on which their secrecy diversity gains are determined through an asymptotic intercept probability analysis in the high signal-to-noise ratio (SNR) region. It is proved that the conventional non-cooperation exhibits a secrecy diversity of zero, whereas the proposed SC-RJS and SC-OJS achieve a higher secrecy diversity of one. This also surprisingly means that no additional secrecy diversity gain is achieved by the optimal jammer selection compared to the random selection strategy. In addition, numerical results show that the intercept probability performance of the SC-OJS is always better than that of the SC-RJS and non-cooperation, even when the legitimate channel is worse than the eavesdropping channel. © 2016 IEEE.

Yun L.,Nanjing University of Posts and Telecommunications
Optics Express | Year: 2017

We report the generation of both polarization-locked vector dissipative soliton and group velocity-locked vector conventional soliton in a nanotube-mode-locked fiber ring laser with large normal dispersion, for the first time to our best knowledge. Depending on the polarization-depended extinction ratio of the fiber-based Lyot filter, the two types of vector solitons can be switched by simply tuning the polarization controller. In the case of low filter extinction ratio, the output vector dissipative soliton exhibits steep spectral edges and strong frequency chirp, which presents a typical pulse duration of ~23.4 ps, and can be further compressed to ~0.9 ps. In the contrastive case of high filter extinction ratio, the vector conventional soliton has clear Kelly sidebands with transform-limited pulse duration of ~1.8 ps. Our study provides a new and simple method to achieve two different vector soliton sources, which is attractive for potential applications requiring different pulse profiles. © 2017 Optical Society of America.

Zhou L.,Nanjing University of Posts and Telecommunications
Quantum Information Processing | Year: 2013

We present two entanglement concentration protocols (ECPs) for arbitrary three-electron W state based on their charges and spins. Different from other ECPs, with the help of the electronic polarization beam splitter and charge detection, the less-entangled W state can be concentrated into a maximally entangled state only with some single charge qubits. The second ECP is more optimal than the first one, for by constructing the complete parity check gate, the second ECP can be used repeatedly to further concentrate the less-entangled state and obtain a higher success probability. Therefore, both the ECPs especially the second one may be useful in current quantum information processing. © Springer Science+Business Media New York 2012.

Zhao Q.,Fudan University | Zhao Q.,Nanjing University of Posts and Telecommunications | Li F.,Fudan University | Huang C.,Fudan University
Chemical Society Reviews | Year: 2010

Recently, the use of phosphorescent heavy-metal complexes as chemosensors has attracted increasing interest due to their advantageous photophysical properties. This critical review focuses on the design principles and the recent development of phosphorescent chemosensors for metal cations, anions, pH, oxygen, volatile organic compounds and biomolecules based on some heavy-metal complexes (such as Pt(ii)-, Ru(ii)-, Re(i)-, Ir(iii)-, Cu(i)-, Au(i)- and Os(ii)-based complexes), in which the variation in phosphorescence signals induced by the interaction between heavy-metal complexes and analytes is utilized (217 references). © 2010 The Royal Society of Chemistry.

Jiang H.,Nanjing University of Posts and Telecommunications
Small | Year: 2011

Graphene is a flat monolayer of carbon atoms packed tightly into a 2D honeycomb lattice that shows many intriguing properties meeting the key requirements for the implementation of highly excellent sensors, and all kinds of proof-of-concept sensors have been devised. To realize the potential sensor applications, the key is to synthesize graphene in a controlled way to achieve enhanced solution-processing capabilities, and at the same time to maintain or even improve the intrinsic properties of graphene. Several production techniques for graphene-based nanomaterials have been developed, ranging from the mechanical cleavage and chemical exfoliation of high-quality graphene to direct growth onto different substrates and the chemical routes using graphite oxide as a precusor to the newly developed bottom-up approach at the molecular level. The current review critically explores the recent progress on the chemical preparation of graphene-based nanomaterials and their applications in sensors. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sheng Y.-B.,Nanjing University of Posts and Telecommunications | Zhou L.,Nanjing University of Posts and Telecommunications
Journal of the Optical Society of America B: Optical Physics | Year: 2013

We present an entanglement concentration protocol (ECP) for the less-entangled W-state with quantum-dot and microcavity coupled systems. The present protocol uses quantum nondemolition measurement on the spin parity to construct the hybrid parity check gate. Different from other ECPs, the less-entangled W-state with quantum-dot and microcavity coupled systems can be concentrated with the help of some single photons. The most significant advantage is that during the whole ECP, we do not destroy the W-state and only consume some local single photons. The whole protocol can be repeated to obtain a higher success probability. It may be useful in current quantum information processing. © 2013 Optical Society of America.

Huang X.,National University of Singapore | Han S.,National University of Singapore | Huang W.,Nanjing University of Technology | Huang W.,Nanjing University of Posts and Telecommunications | And 2 more authors.
Chemical Society Reviews | Year: 2013

Photovoltaic (PV) technologies for solar energy conversion represent promising routes to green and renewable energy generation. Despite relevant PV technologies being available for more than half a century, the production of solar energy remains costly, largely owing to low power conversion efficiencies of solar cells. The main difficulty in improving the efficiency of PV energy conversion lies in the spectral mismatch between the energy distribution of photons in the incident solar spectrum and the bandgap of a semiconductor material. In recent years, luminescent materials, which are capable of converting a broad spectrum of light into photons of a particular wavelength, have been synthesized and used to minimize the losses in the solar-cell-based energy conversion process. In this review, we will survey recent progress in the development of spectral converters, with a particular emphasis on lanthanide-based upconversion, quantum-cutting and down-shifting materials, for PV applications. In addition, we will also present technical challenges that arise in developing cost-effective high-performance solar cells based on these luminescent materials.

Yang Y.,Fudan University | Zhao Q.,Nanjing University of Posts and Telecommunications | Feng W.,Fudan University | Li F.,Fudan University
Chemical Reviews | Year: 2013

Chemodosimeters in luminescence bioimaging have attracted increasing attention and become a very active research field because of their rapid response, high sensitivity, and excellent selectivity. Chemodosimeters are used to detect a target analyte through a usually irreversible chemical reaction between the dosimeter molecule and the analyte. Hence, the selectivity of chemodosimeters for the target analyte is often very high. Luminescent chemodosimeters provide a useful alternative to chemosensors for detecting analytes in biological systems, especially for detecting heavy-metal cations, which often cause luminescence quenching in chemosensor systems. The most reported luminescent chemodosimeters have been based on fluorescence turn-on, or emission wavelength shifts, which makes them ideal for application in bioimaging. Besides molecular design, it is also important to understand better the cellular uptake behavior of luminescent chemodosimeters for bioimaging application.

Zhao Q.,Fudan University | Zhao Q.,Nanjing University of Posts and Telecommunications | Huang C.,Fudan University | Li F.,Fudan University
Chemical Society Reviews | Year: 2011

The application of phosphorescent heavy-metal complexes with d6, d8 and d10 electron configurations for bioimaging is a new and promising research field and has been attracting increasing interest. In this critical review, we systematically evaluate the advantages of phosphorescent heavy-metal complexes as bioimaging probes, including their photophysical properties, cytotoxicity and cellular uptake mechanisms. The progress of research into the use of phosphorescent heavy-metal complexes for staining different compartments of cells, monitoring intracellular functional species, providing targeted bioimaging, two-photon bioimaging, small-animal bioimaging, multimodal bioimaging and time-resolved bioimaging is summarized. In addition, several possible future directions in this field are also discussed (133 references). © 2011 The Royal Society of Chemistry.

Zou Y.,Nanjing University of Posts and Telecommunications | Yao Y.-D.,Stevens Institute of Technology | Zheng B.,Nanjing University of Posts and Telecommunications
IEEE Communications Magazine | Year: 2012

Cognitive radio is a promising technology that enables an unlicensed user (also known as a cognitive user) to identify the white space of a licensed spectrum band (called a spectrum hole) and utilize the detected spectrum hole for its data transmissions. To design a reliable and efficient cognitive radio system, there are two fundamental issues: to devise an accurate and robust spectrum sensing algorithm to detect spectrum holes as accurately as possible; and to design a secondary user transmission mechanism for the cognitive user to utilize the detected spectrum holes as efficiently as possible. This article investigates and shows that cooperative relay technology can significantly benefit the abovementioned two issues, spectrum sensing and secondary transmissions. We summarize existing research about the application of cooperative relays for spectrum sensing (referred to as the cooperative sensing) and address the related potential challenges. We discuss the use of cooperative relays for the secondary transmissions with a primary user's quality-of-service (QoS) constraint, for which a diversity-multiplexing trade-off is developed. In addition, this article shows a trade-off design of cognitive transmissions with cooperative relays by jointly considering the spectrum sensing and secondary transmissions in cognitive radio networks. © 1979-2012 IEEE.

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