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Singlet Oxygen Generation and Photoinduced Charge Separation of Tetra Polyethyleneglycol Functionalized Zinc Phthalocyanine-Fullerene dyad

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Chinese Journal of Chemistry 2016年第10期34卷 969-974页

作者： Habtom B. Gobeze Ta Tram Chandra B. KC Robert R. Cantu Paul A. Karr francis d'souza department of Chemistry University of North Texas 1155 Union Circle #305070 Denton TX 76203-5017 USA department of Physical Sciences and Mathematics Wayne State College 111 Main Street Wayne Nebraska 68787 USA Advanced Materials and Manufacturing Processes Institute (A MMPI) UNT-Discovery Park 3940 N. Elm St. #E132 Denton TX 76207-7102 USA

Utilization of polyethyleneglycol （PEG） functionalized zinc phthalocyanine, （PEG）4ZnPc in （i） singlet oxygen generation, and （ii） in building energy harvesting donor-acceptor systems using fullerene, C60 as an acceptor via the well-known metal-ligand axial coordination approach is reported. The （PEG）4ZnPe was found to be capable of producing singlet oxygen with a quantum yield, ooa of 0.77 in toluene, a value higher than that obtained for pristine （t-bu）4ZnPc （φ△=0.54） carrying no PEG groups, revealing its usefulness in photodynamic therapy applications. Spectroscopic studies revealed efficient binding of phenylimidazole functionalized fullerene, C60 Im with l ： 1 stoichiometry to （PEG）4ZnPc. Binding constant K for the formation of （PEG）4ZnPc：ImC60 dyad was found to be 6 × 103 M 1 revealing moderate stability. Geometric and electronic studies of the dyad was arrived by B3LYP/3-21G（＊） method. The HOMO level was found to be on zinc phthalocyanine entity while the LUMO level was found to be on the C60 entity suggesting formation of （PEG）4ZnPc＊＋：ImC60＊ charge separated state during the process of electron transfer reaction. Redox studies on the （PEG）4ZnPc：ImC60 dyad enabled accurate determination of the oxidation and reduction potentials of the donor-acceptor system, and to evaluate free-energy changes associated for the charge separation process. Kinetics of photoinduced charge separation and recombination in the （PEG）4ZnPc：ImC60 dyad was investigated using femtosecond transient absorption studies. Relatively long-lived charge separated states were confirmed for the dyad suggesting their potential usefulness in energy harvesting applications.

关键词： singlet oxygen photoinduced charge separation zinc phthalocyanine fullerene self-assembly

Absorption and emission modulation in a MoS2–GaN（0001） heterostructure by interface phonon–exciton coupling

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Photonics Research 2019年第12期7卷 1511-1520页

作者： YUBA POUdEL JAGOdA SLAWINSKA PRIYA GOPAL SAIRAMAN SEETHARAMAN ZACHARIAH HENNIGHAUSEN SWASTIK KAR francis d'souza MARCO BUONGIORNO NARdELLI ARUP NEOGI department of Physics University of North TexasDentonTexas 76203USA department of Chemistry University of North TexasDentonTexas 76203USA department of Physics Northeastern UniversityBostonMassachusetts 02115USA

Semiconductor heterostructures based on layered two-dimensional transition metal dichalcogenides(TMds)interfaced to gallium nitride(Ga N)are excellent material systems to realize broadband light absorbers and emitters due to their close proximity in the lattice *** surface properties of a polar semiconductor such as Ga N are dominated by interface phonons,and thus the optical properties of the vertical heterostructure are influenced by the coupling of these carriers with *** activation of different Raman modes in the heterostructure caused by the coupling between interfacial phonons and optically generated carriers in a monolayer MoS_2–Ga N(0001)heterostructure is *** excitonic states in MoS_2 are close to the interband energy state of intraband defect state of Ga *** functional theory(dFT)calculations are performed to determine the band alignment of the interface and revealed a type-I *** close proximity of the energy levels and the excitonic states in the semiconductors and the coupling of the electronic states with phonons result in the modification of carrier relaxation *** of the excitonic absorption states in MoS_2 is measured by transient optical pump-probe spectroscopy and the change in emission properties of both semiconductors is measured by steady-state photoluminescence(PL)emission *** is significant red-shift of the C excitonic band and faster dephasing of carriers in MoS_***,optical excitation at energy higher than the bandgap of both semiconductors slows down the dephasing of carriers and energy exchange at the *** and blue-shifted PL emission is observed in MoS_*** N band-edge emission is reduced in intensity at room temperature due to increased phonon-induced scattering of carriers in the Ga N *** results demonstrate the relevance of interface coupling between the semiconductors for the development of optical and electronic applications.

关键词： spectroscopy. coupling interface

Climate Optimum rejuvenates the Mediterranean marine world

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Integrative Zoology 2010年第2期5卷 112-121页

作者： francis d.POR department of Evolution Systematics and Ecology the National Collections of Natural HistoryHebrew University of JerusalemJerusalemIsrael

The Mediterranean,a sea with an already eventful history,is again undergoing an extreme change.A combination of general warming of the Mediterranean Sea and contact with the Indopacific world through the Suez Canal has set the stage for massive changes in the biota that inhabit this *** over a century,tropical species of all taxa have been migrating back into the Mediterranean,suggesting a duplication or restoration of a mid-Pliocene Piacenzian or late Miocene Tortonian *** cases are presented in three major *** is not a serial invasion by individual rogue exotic and damaging species,as often wrongly assumed and *** its unique biogeographic magnitude being recognized,an opportunity to study the progress of this phenomenon is being *** is because of the changed priorities in research,the acute taxonomic impediment and to the geopolitical difficulties in ***,the limitations of the restoration process are defined and a careful future outlook is presented.

关键词： climate optimum Lessepsian migration Mediterranean biota Tethys tropical restoration

deuterobiosphere the Chemosynthetic Second Biosphere of the Globe. A First Review

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Integrative Zoology 2008年第2期3卷 101-114页

作者： francis d.POR The Scientific Collections The Life Sciences InstituteThe Hebrew UniversityIsrael

With the discovery of Ophel, a chemosynthesis-based continental subterranean environment (Por 2007), it becameevident that such environments, previously known only from the sea , are spanning the world as a parallel biosphere,the deuterobiosphere. In this preliminary contribution the different known biomes of the deuterobiosphere arereviewed and some general and comparative features are listed.

关键词： anchialine systems chemosynthetic environments cold seeps deuterobiosphere hot vents Ophel thiobios

Evidence for Vacancy Injection during the Oxidation of Iron

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中国腐蚀与防护学报 2009年第4期29卷 293-295页

作者： d.G.LEES R.francis School of Materials University of ManchesterGosvenor StreetManchester M1 7HS UK

Iron discs have been oxidised at 890℃on one side only,with the other side protected by an inert *** scale-metal adhesion was very ***,scale-metal adhesion was maintained by the scale relaxing towards the metal but after a time which depended upon the initial metal thickness,oxide relaxation ceased and the inert face moved towards the scale-metal *** the face which was normally inert was coveredwith a non-growing oxide layer,the scale-metal adhesion *** results show that vacancies which were produced by oxidation were annihilated within the metal,that the inert face played a part and that the scale-metal interface is not a good sink for vacancies.

关键词：金属腐蚀防护铁材料

determination of contact parameters for discrete element method simulations of granular systems

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Particuology 2008年第6期6卷 521-528页

作者： Kevin francis Malone Institute of Particle Science and Engineering University of Leeds

Both linear-spring-dashpot （LSd） and non-linear Hertzian-spring-dashpot （HSd） contact models are commonly used for the calculation of contact forces in discrete Element Method （dEM） simulations of granular systems. despite the popularity of these models, determination of suitable values for the contact parameters of the simulated particles such as stiffness, damping coefficient, coefficient of restitution, and simulation time step, is not altogether obvious. In this work the relationships between these contact parameters for a model system where a particle impacts on a flat base are examined. Recommendations are made concerning the determination of these contact parameters for use in dEM simulations.

关键词： discrete Element Method (dEM) Linear-spring--dashpot model Non-linear Hertzian-spring-dashpot model Contact parameters

Neutrino astronomy： An update

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Frontiers of physics 2013年第6期8卷 759-770页

作者： francis Halzen Wisconsin IceCube Particle Astrophysics Center (WIPAC) and department of Physics University of Wisconsin Madison WI 53706 USA

detecting neutrinos associated with the still enigmatic sources of cosmic rays has reached a new watershed with the completion of IceCube, the first detector with sensitivity to the anticipated fluxes. In this review, we will briefly revisit the rationale for constructing kilometer-scale neutrino detectors and summarize the status of the field.

关键词： neutrinos cosmic rays astrophysics

No country is an island in regulating food safety:How the WTO monitors Chinese food safety laws through the Trade Policy Review Mechanism(TPRM)

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Journal of Integrative Agriculture 2015年第11期14卷 2142-2156页

作者： francis Snyder Northwest A&F University School of Transnational Law Peking University Shenzhen Graduate School College of Europe

Established within the framework of the World Trade Organization （WTO）, the Trade Policy Review Mechanism （TPRM） reviews periodically the trade policies of all WTO Members. The review includes many aspects of food safety regulation. China＇s trade policy is reviewed every two years. This paper analyses in detail the reviews of China＇s trade policy in 2006, 2008, 2010, 2012 and 2014. It focuses in particular on food safety laws and types of standards, alignment of domestic standards with international standards, the role of different domestic institutions, transparency and notification of food safety measures under the WTO agreements on Sanitary and Phytosanitary Measures （SPS） and on Technical Barriers to Trade （TBTAgreement）, import and export, and geographical indications （GIs）. It concludes that the WTO TPRM can contribute, within its mandate, to reform of Chinese food safety laws and improvement of food safety in China. it notes that China has already undertaken substantial reforms of its system for regulating food safety. It recommends that China should continue to participate actively in the TPRM, follow its own path with regard to alignment and learn selectively from other WTO Members.

关键词： food safety food standards public health consumer welfare China Chinese food safety laws World Trade Organization WTO law Trade Policy Review Mechanism (TPRM) SPS Agreement TBT Agreement

Topological Studies of Three-dimensional Flows in a High Pressure Compressor Stator Blade Row without and with Boundary Layer Aspiration

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Chinese Journal of Aeronautics 2011年第5期24卷 541-549页

作者： Ankit SACHdEVA francis LEBOEUF Laboratoire de Mécanique des Fluides et d'Acoustique Ecole Centrale de Lyon

This paper presents a numerical study of the flow topologies of three-dimensional （3d） flows in a high pressure compressor stator blade row without and with boundary layer aspiration on the hub wall. The stator blade is representative of the first stage operating under transonic inlet conditions and the blade design encourages development of highly complex 3d flows. The blade has a small tip clearance. The computational fluid dynamics （CFd） studies show progressive increase of hub corner stall with the increase in incidence. Aspiration is implemented on the hub wall via a slot in the comer between the hub wall and the suction surface. The CFd studies show aspiration to be sensitive to the suction flow rate; lower rate leads to very complex flow struc- tures and increased level of losses whereas higher rate renders aspiration effective for control of hub comer separation. The flow topologies are studied by trace of skin friction lines on the walls. The nature of flow can be explained by the topological rules of closed separation. Furthermore, a deeper analysis is done for a particular case with advanced criterion to test the non-degeneracy of critical points in the flow field.

关键词： high pressure compressor flow topologies three-dimensional flows boundary layer aspiration tip clearance