Browsing by Author "Wang, X."

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    48 W continuous-wave output power with high efficiency from a single emitter laser diode at 915 nm
    (SPIE - International Society for Optical Engineering, 2023-03-14) Yang, G.; Liu, Y.; Zhao, Yongming; Tang, S.; Zhao, Yuliang; Lan, Y.; Bai, L.; Li, Y.; Wang, X.; Demir, Abdullah; Zediker, Mark S.; Zucker, Erik P.
    Improving the power and efficiency of 9xx-nm broad-area laser diodes reduces the cost of laser systems and expands applications. LDs with more than 25 W output power combined with power conversion efficiency (PCE) above 65% can provide a cost-effective high-power laser module. We report a high output power and high conversion efficiency laser diode operating at 915 nm by investigating the influence of the laser internal parameters on its output. The asymmetric epitaxial structure is optimized to achieve low optical loss while considering high internal efficiency, low series resistance, and modest optical confinement factor. Experimental results show an internal optical loss of 0.31 cm-1 and internal efficiency of 96%, in agreement with our simulation results. Laser diodes with 230 μm emitter width and 5 mm cavity length have T0 and T1 characteristic temperatures of 152 and 567 K, respectively. The maximum power conversion efficiency reaches 74.2% at 5 °C and 72.6% at 25 °C, and the maximum output power is 48.5 W at 48 A (at 30 ℃), the highest reported for a 9xx-nm single emitter laser diode. At 25 oC, a high PCE of 67.5% is achieved for the operating power of 30 W at 27.5 A, and the lateral far-field angle with 95% power content is around 8°. Life test results show no failure in 1200 hours for 55 laser diodes. In addition, 55.5 W output was achieved at 55 A from a laser diode with 400 μm emitter width and 5.5 mm cavity length. A high PCE of 64.3% is obtained at 50 W with 47 A. © 2023 SPIE.
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    Efficient synthesis of plate-like crystalline hydrated tungsten trioxide thin films with highly improved electrochromic performance
    (Royal Society of Chemistry, 2011) Jiao, Z.; Wang, X.; Wang, J.; Ke, L.; Demir, Hilmi Volkan; Koh, T. W.; Sun, X. W.
    Plate-like hydrated tungsten trioxide (3WO(3)center dot H(2)O) films were grown on a fluorine doped tin oxide (FTO) coated transparent conductive substrate via an efficient, facile and template-free hydrothermal method. The film exhibited a fast coloration/bleaching response (t(c90%) = 4.3 s and t(b90%) = 1.4 s) and a high coloration efficiency (112.7 cm(2) C(-1)), which were probably due to a large surface area.
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    A global effort to define the human genetics of protective immunity to SARS-CoV-2 infection
    (Elsevier, 2020) Casanova, J.-L.; Su, H. C.; Abel, L.; Aiuti, A.; Almuhsen, S.; Arias, A. A.; Bastard, P.; Biggs, C.; Bogunovic, D.; Boisson, B.; Boisson-Dupuis, S.; Bolze, A.; Bondarenko, A.; Bousfiha, A.; Brodin, P.; Bustamante, J.; Butte, M.; Casari, G.; Ciancanelli, M.; Cobat, A.; Condino-Neto, A.; Cooper, M.; Dalgard, C.; Espinosa, S.; Feldman, H.; Fellay, J.; Franco, J. L.; Hagin, D.; Itan, Y.; Jouanguy, E.; Lucas, C.; Mansouri, D.; Meyts, I.; Milner, J.; Mogensen, T.; Morio, T.; Ng, L.; Notarangelo, L. D.; Okada, S.; Özçelik, Tayfun; Palacín, P. S.; Planas, A.; Prando, C.; Puel, A.; Pujol, A.; Redin, C.; Renia, L.; Gallego, J. C. R.; Quintana-Murci, L.; Sancho-Shimizu, V.; Sankaran, V.; Seppänen, M. R. J.; Shahrooei, M.; Snow, A.; Spaan, A.; Tangye, S.; Tur, J. P.; Turvey, S.; Vinh, D. C.; von Bernuth, H.; Wang, X.; Zawadzki, P.; Zhang, Q.; Zhang, S.
    SARS-CoV-2 infection displays immense inter-individual clinical variability, ranging from silent infection to lethal disease. The role of human genetics in determining clinical response to the virus remains unclear. Studies of outliers—individuals remaining uninfected despite viral exposure and healthy young patients with life-threatening disease—present a unique opportunity to reveal human genetic determinants of infection and disease.
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    Photovoltaic nanopillar radial junction diode architecture enhanced by integrating semiconductor quantum dot nanocrystals as light harvesters
    (American Institute of Physics, 2010-09-03) Güzeltürk, B.; Mutlugün, E.; Wang, X.; Pey, K. L.; Demir, Hilmi Volkan
    We propose and demonstrate colloidal quantum dot hybridized, radial p-n junction based, nanopillar solar cells with photovoltaic performance enhanced by intimately integrating nanocrystals to serve as light harvesting agents around the light trapping pillars. By furnishing Si based nanopillar photovoltaic diodes with CdSe quantum dots, we experimentally showed up to sixfold enhancement in UV responsivity and ∼13% enhancement in overall solar conversion efficiency. The maximum responsivity enhancement achieved by incorporation of nanocrystals in the nanopillar architecture is found to be spectrally more than four times larger than the responsivity enhancement obtained using planar architecture of the same device.
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    Privacy in the genomic era
    (Association for Computing Machinery, 2015) Naveed, M.; Ayday, E.; Clayton, E.W.; Fellay J.; Gunter, C.A.; Hubaux J.-P.; Malin, B.A.; Wang, X.
    Genome sequencing technology has advanced at a rapid pace and it is now possible to generate highlydetailed genotypes inexpensively. The collection and analysis of such data has the potential to support various applications, including personalized medical services. While the benefits of the genomics revolution are trumpeted by the biomedical community, the increased availability of such data has major implications for personal privacy; notably because the genome has certain essential features, which include (but are not limited to) (i) an association with traits and certain diseases, (ii) identification capability (e.g., forensics), and (iii) revelation of family relationships. Moreover, direct-to-consumer DNA testing increases the likelihood that genome data will be made available in less regulated environments, such as the Internet and for-profit companies. The problem of genome data privacy thus resides at the crossroads of computer science, medicine, and public policy. While the computer scientists have addressed data privacy for various data types, there has been less attention dedicated to genomic data. Thus, the goal of this paper is to provide a systematization of knowledge for the computer science community. In doing so, we address some of the (sometimes erroneous) beliefs of this field and we report on a survey we conducted about genome data privacy with biomedical specialists. Then, after characterizing the genome privacy problem, we review the state-of-the-art regarding privacy attacks on genomic data and strategies for mitigating such attacks, as well as contextualizing these attacks from the perspective of medicine and public policy. This paper concludes with an enumeration of the challenges for genome data privacy and presents a framework to systematize the analysis of threats and the design of countermeasures as the field moves forward. © 2015 ACM 0360-0300/2015/08-ART6 $15.00.