| 1. |
- Adcox, K, et al.
(author)
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Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX Collaboration
- 2005
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In: Nuclear Physics, Section A. - : Elsevier BV. - 0375-9474. ; 757:1-2, s. 184-283
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Research review (peer-reviewed)abstract
- Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons in a wide range of transverse momenta (PT), elliptic flow, two-particle correlations, nonstatistical fluctuations, and suppression of particle production at high PT. The results are examined with an emphasis on implications for the formation of a new state of dense matter. We find that the state of matter created at RHIC cannot be described in terms of ordinary color neutral hadrons.
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| 2. |
- Feng, Yanli, et al.
(author)
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A supramolecular photoswitch constructed by intermolecular hydrogen bond between BTEPy and TTF-COOH
- 2008
-
In: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 455:4-6, s. 256-260
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Journal article (peer-reviewed)abstract
- A novel supramolecular photoswitch containing bisthienylethene- pyridine (BTEPy) and carboxyl attached tetrathiafluvalene (TTF-COOH) was constructed via intermolecular hydrogen bond. FT-IR spectra, XPS characterizations, H-1 NMR and theoretical calculation were carried out to verify the formation of the intermolecular hydrogen bond. The supramolecular self-assemblies BTEPy 2TTF show good photo-chromic properties. A molecular switch with UV/vis light as inputs and electrochemical signals as outputs was obtained.
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| 3. |
- Li, Xin, et al.
(author)
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Nuclear magnetic shielding of the Cd-113(II) ion in aqua solution : A combined molecular dynamics/density functional theory study
- 2008
-
In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 112:36, s. 11347-11352
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Journal article (peer-reviewed)abstract
- We present a combined molecular dynamics simulation and density functional theory investigation of the nuclear magnetic shielding constant of the Cd-113(II) ion solvated in aqueous solution. Molecular dynamics simulations are carried out for the cadmium-water system in order to produce instantaneous geometries for subsequent determination of the nuclear magnetic shielding constant at the density functional theory level. The nuclear magnetic shielding constant is computed using a perturbation theory formalism, which includes nonrelativistic and leading order relativistic contributions to the nuclear magnetic Shielding tensor. Although the NMR shielding constant varies significantly with respect to simulation time, the value averaged over increasing number of snapshots remains almost constant. The paramagnetic nonrelativistic contribution is found to be most sensitive to dynamical changes in the system and is mainly responsible for the thermal and solvent effects in solution. The relativistic correction features very little sensitivity to the chemical environment, and can be disregarded in theoretical calculations when a Cd complex is used as reference compound in Cd-113 NMR experiments, due to the mutual cancelation between individual relativistic corrections.
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| 4. |
- Li, Xin, et al.
(author)
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Paramagnetic Perturbation of the F-19 NMR Chemical Shift in Fluorinated Cysteine by O-2 : A Theoretical Study
- 2009
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In: Journal of Physical Chemistry B. - Washington, D. C. : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 113:31, s. 10916-10922
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Journal article (peer-reviewed)abstract
- We present a combined molecular dynamics and density functional theory study of dioxygen-induced perturbation of the F-19 NMR chemical shifts in an aqueous solution of fluorinated cysteine under 100 atm of O-2 partial pressure. Molecular dynamics Simulations are carried out to determine the dominant structures of O-2 and the fluorinated cysteine complexes in water, and the collected structural information is exploited in computation of F-19 chemical shifts using density functional theory. The obtained results indicate that the density redistribution of the O-2 unpaired electrons between the dioxygen and fluorinated cysteine is responsible for the experimentally observed perturbation of the F-19 NMR chemical shifts, where the Fermi contact interaction plays the key role. The O-2-induced paramagnetic F-19 chemical shift, averaged over the simulation trajectory, is comparable with the reported experimental values, proving the availability of the developed strategy for modeling F-19 NMR chemical shifts in the presence of paramagnetic agents in ail aqueous solution. The applicability of the combined molecular dynamics/density functional theory approach for dioxygen NMR perturbation to all resonating nuclei including H-1, C-13, N-15, and F-19 is emphasized, and the ramification of this for investigations of membrane protein structures is discussed.
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| 5. |
- Meng, Xianle, et al.
(author)
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Novel Bisthienylethenes Containing Naphthalimide as the Center Ethene Bridge : Photochromism and Solvatochromism for Combined NOR and INHIBIT Logic Gates
- 2008
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In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 112:49, s. 15636-15645
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Journal article (peer-reviewed)abstract
- Two novel photochromic bisthienylethene derivatives BTE-NA1 and BTE-NA2 with a six-membered aryl ring of naphthalimide fluorescent moiety as the center ethene bridging unit were synthesized and fully characterized by H-1 NMR, C-13 NMR, and HRMS. They exhibit considerably high cyclization quantum yield and good fatigue resistance. Interestingly, the fluorescence of BTE-NA1 arising from the naphthalimide unit could be well modulated by photochromism and solvatochromism. Quantum chemical calculations were carried out to study their geometrical, electronic, and optical properties, which were in good accordance with the experimental data. Furthermore, a combined NOR and INHIBIT logic operation based on BTE-NA1 has been successfully mimicked with fluorescence changes as outputs.
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| 6. |
- Ning, Zhijun, et al.
(author)
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Novel iridium complex with carboxyl pyridyl ligand for dye-sensitized solar cells : High fluorescence intensity, high electron injection efficiency?
- 2009
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In: Journal of Organometallic Chemistry. - : Elsevier BV. - 0022-328X .- 1872-8561. ; 694:17, s. 2705-2711
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Journal article (peer-reviewed)abstract
- Novel iridium-based sensitizers Iridium(III) bis[2-phenylpyridinato-N,C-2']-5-carboxylpicolinate) (Ir1), Iridium(III) bis[2-(naphthalen-1-yl) pyridinato-N,C-2']-5-carboxyl-picolinate) (Ir2), Iridium(III) bis[2-phenylpyridinato-N, C-2']-4,4'-(dicarboxylicacid)-2,2'-bipyridine (Ir3) were synthesized for sensitization of mesoscopic titanium dioxide injection solar cells. By changing the ligand, the absorption spectra can be extended and molar extinction coefficient was enhanced. The dye-sensitized nanocrystalline TiO2 solar cells (DSSCs) based on dye Ir3 showed the best photovoltaic performance: a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 85%, a short-circuit photocurrent density (J(sc)) of 9.59 mA cm (2), an open-circuit photovoltage (V-oc) of 0.552 V, and a fill factor (ff) of 0.54, corresponding to an overall conversion efficiency of 2.86% under AM 1.5 sun light. Moreover, the HOMO and LUMO energy levels tuning can be conveniently accomplished by alternating the ligand. The high oxidative potential of Ir3 enables it to be used along with Br-/Br-3(-) redox electrolyte and the photovoltage was found to be enhanced greatly.
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| 7. |
- Ning, Zhijun, et al.
(author)
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Photovoltage Improvement for Dye-Sensitized Solar Cells via Cone-Shaped Structural Design
- 2009
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In: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 113:23, s. 10307-10313
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Journal article (peer-reviewed)abstract
- In this article, three truexene-based dyes with 2-cyanoacrylic acid as acceptor and starburst triarylamine as donor (S5, S6, and S7) were conveniently synthesized and used for dye-sensitized solar cells (DSSCs). A compact sensitizer layer is molecular interfacially engineered on the TiO2 surface via cone-shaped sensitizers. As a result, the approach of the electrolyte to the TiO2 surface is blocked significantly by the compact sensitizer layer formed and the charge recombination in the DSSCs is proved to be retarded effectively. The monochromatic incident photon-to-current conversion efficiency of these sensitizers is near 90%. In addition, S7-sensitized solar cells yield an open-circuit voltage of 752 mV and it fill factor of 0.70, which are even higher than those of N719 under the same conditions.
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| 8. |
- Ning, Zhijun, et al.
(author)
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Starburst triarylamine based dyes for efficient dye-sensitized solar cells
- 2008
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In: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 73:10, s. 3791-3797
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Journal article (peer-reviewed)abstract
- We report here on the synthesis and photophysical/electrochemical properties of a series of novel starburst triarylamine-based organic dyes (S1, S2, S3, and S4) as well as their application in dye-sensitized nanocrystalline TiO2 solar cells (DSSCs). For the four designed dyes, the starburst triarylamine group and the cyanoacetic acid take the role of electron donor and electron acceptor, respectively. It was found that the introduction of starburst triarylamine group to form the D-D-pi-A configuration brought about superior performance over the simple D-pi-A configuration, in terms of bathochromically extended absorption spectra, enhanced molar extinction coefficients and better thermo-stability. Moreover, the HOMO and LUMO energy levels tuning can be conveniently accomplished by alternating the donor moiety, which was confirmed by electrochemical measurements and theoretical calculations. The DSSCs based on the dye S4 showed the best photovoltaic performance: a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 85%, a short-circuit photocurrent density (J(sc)) of 13.8 mA cm(-2), an open-circuit photovoltage (V-oc) of 0.63 V, and a fill factor (ff) of 0.69, corresponding to an overall conversion efficiency of 6.02% under 100 mW cm(-)2 irradiation. This work suggests that the dyes based on starburst triphenylamine donor are promising candidates for improvement of the performance of the DSSCs.
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| 9. |
- Su, Min, et al.
(author)
-
Temporal trends of esophageal cancer during 1995-2004 in Nanao Island, an extremely high-risk area in China
- 2007
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In: European Journal of Epidemiology. - : Springer Science and Business Media LLC. - 1573-7284 .- 0393-2990. ; 22:1, s. 43-48
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Journal article (peer-reviewed)abstract
- The purpose of our study was to investigate the temporal malignant tumor incidence rates among the 70,000 residents at the relatively isolated Nanao Island in South China Sea. The data on all malignant tumor cases from Nanao Cancer Registry during 1995-2004 were coded, computerized, and analyzed using the software SPSS10.0. The tumor incident cases, crude incident rate, age-standardized incidence rate, their sex distribution and temporal trend were assessed. A total of 1450 new cancer cases (990 males and 460 females) were identified. The annual average age-standardized incidence rate (ASR) of malignant tumors was 208.18/100,000. The age-standardized incidence rate of the ten leading cancers in both sexes combined per 100,000 population were 74.47 for esophageal cancer (EC), 34.81 for cardiac cancer (CC), 25.66 for liver cancer, 26.01 for lung cancer, 18.52 for stomach cancer, 4.45 for nasopharyngeal cancer, 3.91 for breast cancer, 2.53 for colon/rectum cancer, 2.45 for bladder cancer and 1.92 for pancreatic cancer. These ten types of cancers make up to 93% of all cancer cases, with EC and CC being the most prevalent and making up 52% of the total cases. The incidence rates of esophagus, liver, lung, breast, nasopharyngeal, and colon/rectum cancers showed increasing trends during the period from 1995 to 2004 in Nanao Island. Astounding the EC ASR were 72-150/100,000 among male and 26-64/100,000 among female in Nanao Island during 1995-2004. The EC incidence rate in Nanao population is among the highest across the world, which suggests that there are potential genetic and/or environmental factors affecting this particular population.
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| 10. |
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| 11. |
- Tian, Yu-peng, et al.
(author)
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Synthesis, crystal structure and NLO properties of a novel ruthenium(II) complex with unusual coordination mode
- 2005
-
In: Transition metal chemistry (Weinheim). - : Kluwer Academic Publishers. - 0340-4285 .- 1572-901X. ; 30:7, s. 778-785
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Journal article (peer-reviewed)abstract
- A new Schiff base 4-[N-hydroxyethyl-N-(methyl)amino]benzaldehyde S-methyl dithiocarbazate (HL, where H is a dissociable proton) and the ruthenium complex [Ru(bpy)2L]PF6 (bpy = 2,2′-bipyridine) have been synthesized. The structural determinations of the ligand and its ruthenium complex, by X-ray crystallography, show that the ligand is coordinated as a monoanionic bidentate N, S-donor, forming a four-member chelate ring with a bite angle of 65.91°. The complex shows intense MLCT transitions in the visible region. Fluorescent and electrochemical properties have been also studied. The complex in DMF solution exhibited a strong two-photon absorption (t.p.a.) at 532 nm nanosecond laser pulses. The t.p.a. coefficient β, t.p.a. cross-section σ and the third-order optical nonlinearity χ(3) of the complex and the ligand have been determined by the Z-scan technique.
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| 12. |
- Zhang, Dong, et al.
(author)
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A dual-ion-switched molecular brake based on ferrocene
- 2009
-
In: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; :13, s. 1700-1702
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Journal article (peer-reviewed)abstract
- A new dual-ion-switched molecular brake was synthesized and operated by chemical reagents (H+/OH- and Zn2+/EDTA), and its rotation could be read out by chromogenic, fluorogenic and electrochemical signals.
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| 13. |
- Zhang, Qiong, et al.
(author)
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'Click' synthesis of starburst triphenylamine as potential emitting material
- 2009
-
In: Dyes and pigments. - : Elsevier BV. - 0143-7208 .- 1873-3743. ; 81:1, s. 80-84
-
Journal article (peer-reviewed)abstract
- The efficient synthesis of a starburst triphenylamine, tris(4-(1-(4-(diphenylamino)phenyl)-1H-1,2,3-triazol-4-yl)phenyl)amine, via straightforward 'click coupling' of 4-azido-N,N-diphenylbenzenamine and tris(4-ethynylphenyl)amine is reported. The reaction was performed in THF using (PPh3)(3)CuBr as catalyst and was accomplished within 6 h in high yield (92%). Both the synthesis and purification steps were greatly simplified in comparison with conventional methods. The optical, electrochemical, and thermal properties of the starburst triphenylamine were examined: the synthesized compound emitted deep blue fluorescence in both solution and the solid state and displayed reversible redox processes. The starburst triphenylamine is a potential hole-transporting material and blue-light-emitting material.
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| 14. |
- Zhang, Qing-He, et al.
(author)
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Electrophysiological and behavioral responses of Ips duplicatus to aggregation pheromone in inner mongolia, China: Amitinol as a potential pheromone component
- 2007
-
In: Journal of Chemical Ecology. - : Springer Science and Business Media LLC. - 1573-1561 .- 0098-0331. ; 33:7, s. 1303-1315
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Journal article (peer-reviewed)abstract
- Volatiles from Ips duplicatus male hindgut extracts and aeration samples of spruce logs colonized by the virgin males were analyzed by coupled gas chromatography-mass spectrometry (GC-MS), coupled gas chromatography-electroantennographic detection (GC-EAD), and field trapping bioassays in Inner Mongolia, China. GC-MS analyses showed that males from nuptial chambers (for reproduction) produced hindgut volatile profiles similar to those of maturation feeding males from the nonreproductive galleries. The known aggregation pheromone components, ipsdienol (Id) and E-myrcenol (EM) are the major constituents of this blend, followed by several minor bark beetle-related compounds: 2-methyl-3-buten-2-ol, ipsenol, cis-verbenol, verbenone, 2-phenylethanol, myrtenol, and trans-myrtanol. The enantiomeric composition of the Id from the male hindgut extracts was determined to be a racemic mixture (50/50) by enantioselective GC. GC-EAD experiments indicated that I. duplicatus antennae from both sexes responded strongly not only to the known aggregation pheromone components, Id and EM, but also to the other minor conspecific-produced compounds. The strongest antennal response was elicited by the major pheromone component, Id, which was ca. 2-3 times higher than that elicited by the second component, EM. Electroantennogram dose-responses indicated that antennal response threshold to Id was approximately 100 times lower than that of EM. No synergistic effects between these occurred at peripheral level. A strong and repeatable EAD response was found to a trace compound (flame ionization detection undetectable) from both hindgut and aeration samples. The compound was identified as amitinol (At) based on the retention time and a further EAD analysis of a synthetic mixture. In the field trapping experiments, At increased the attraction of I. duplicatus to the traps baited with a binary blend of EM/Id (1:1) in a synergistic manner when tested at a low release rate (1:1:0.1) but had no effect on catches at the high release rate (1:1:1). This result suggests that At might be a part of the Chinese I. duplicatus aggregation pheromone system. The production ratios of EM/Id from the Inner Mongolian population (EM/Id approximate to 1:2.0-4) were twice as high as those reported from Europe (EM/Id approximate to 1:9), corresponding well with the differences in the optimal response ratios.
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| 15. |
- Zhang, Qiong, et al.
(author)
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Molecular dynamics simulations of local field factors
- 2007
-
In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 127:1
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Journal article (peer-reviewed)abstract
- In the present work, the authors evaluate a scheme based on molecular dynamics to derive local field factors. These are given without any assumption of a cavity by fitting the Langevin functions to the order parameters obtained from the molecular dynamics simulations. The local field factors so obtained, with the detailed chromophore-solvent interactions and solvent structures taken into account, are much smaller than those calculated from the conventional Onsager and Lorentz models. A numerical demonstration is given for two typical organic chromophore molecules, p-nitroaniline and p-nitro-N,N-dimethylaniline dissolved in chloroform.
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| 16. |
- Zhang, Qiong, et al.
(author)
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Molecular dynamics simulations of polycarbonate doped with Lemke chromophores
- 2007
-
In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 111:36, s. 10645-10650
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Journal article (peer-reviewed)abstract
- In the search for optimal electro-optical modulating materials we report in this work molecular dynamics simulations of polycarbonate doped with Lemke chromophores which is a promising candidate system for materials with such functionality. The simulations cover the electric field poling effects on the chromophore order at a temperature above the glass transition temperature (T-g) of the material, the cooling procedure from liquid state to the glass state in the presence of the poling field, and the back relaxation of the system after removal of the field. Our study shows that electric field poling results in a higher chromophore order and that the order is also maintained during the cooling procedure with the poling field applied. In the liquid state, the applied poling field has little effect on the structure of the material. However, after the cooling procedure, the structure changes significantly because the polymer matrix tends to become closely packed. Our study thus indicates that for the bulk material, the structure of the host matrix is very important in determining the performance of the material.
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| 17. |
- Zhu, Liang-Liang, et al.
(author)
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Photolockable Ratiometric Viscosity Sensitivity of Cyclodextrin Polypseudorotaxane with Light-Active Rotor Graft
- 2009
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 25:6, s. 3482-3486
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Journal article (peer-reviewed)abstract
- A prototype, based on light-active fluorescent rotor grafted to beta-cyclodextrin, shows a good solvent viscosity-sensitive behavior due to the environment-dependent nonradiative decay. With the reversible photoisomerization of the cyanostilbene unit, the viscosity sensitivity of the molecular rotor could be locked and activated, and the two switchable states can be distinguished by fluorescent signals. This cyclodextrin derivative was threaded to form a novel polypseudorotaxane. Such supramolecular assembly displays a lockable ratiometric fluorescent viscosity sensitivity with two emission channels: one aroused by fluorophore's intramolecular excimer without influenced by viscosity is used to gauge the concentration of the compound, while the other corresponding to the monomer's rotor fluorescence acts as a viscosity-sensitive signal and it can be shut off by UV irradiation.
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