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21.
In this paper, we report the preparation and red-light-emitting behavior of benzothiadiazole–tris(alkyloxy)phenylethene dyes. In solution, we observed an efficient red light emission with high fluorescence quantum yields (up to 0.78). With increase in solvent polarity, the emission bands shifted to longer wavelengths accompanied by a large Stokes shift of up to 152 nm. A moderate fluorescence quantum yield of 0.52 could be achieved even in the polar solvent dimethylformamide. Red light emission with good fluorescence quantum yields (up to 0.50) was also observed in the bulk solid, liquid, and film state. 相似文献
22.
Takumi Kusano Kenta Fujii Masaaki Tabata Mitsuhiro Shibayama 《Journal of solution chemistry》2013,42(10):1888-1901
Aggregation structures of 1-alkyl-3-methylimidazolium based ionic liquids (ILs) in aqueous solution were investigated by small-angle neutron scattering (SANS) from the viewpoint of alkyl chain length, n, and anions (Cl?, Br? and trifluoromethanesulfonate, $ {\text{CF}}_{3} {\text{SO}}_{3}^{ - } $ ). In [C4mIm+]-based IL systems, no noticeable SANS intensity was observed for all of the systems examined here, although aqueous [C4mIm+][ $ {\text{BF}}_{4}^{ - } $ ] solutions show a significant SANS profile originating from concentration fluctuations in the solution (Almasy et al. J Phys Chem B 112:2382–2387, 2008). This suggests that [C4mIm+][Cl?], [C4mIm+][Br?] and [C4mIm+][ $ {\text{CF}}_{3} {\text{SO}}_{3}^{ - } $ ] homogeneously mix with water, unlike the [C4mIm+][ $ {\text{BF}}_{4}^{ - } $ ] system, due to preferential hydration of the ions. In the case of the C n mIm cations with longer alkyl chain lengths (n = 8 and 12), SANS profiles were clearly observed in the aqueous solutions at IL concentrations of C IL > 230 and 20.0 mmol·dm?3, respectively. For aqueous [C8mIm+][Br?] solutions, the asymptotic behavior of the scattering function varied largely from I(q) ~ q ?2 to ~q ?4 with increasing C IL, indicating that the solution changes from an inhomogeneous mixing state to a nano-scale micelle state. Aqueous [C12mIm+][Br?] solutions show a typical SANS profile for micelle formation in solution. It was found from a model-fitting analysis that the structure of the [C12mIm+][Br?] micelle is ellipsoidal, not spherical, in solutions over the C IL range examined here. 相似文献
23.
Characteristic solution properties of lecithin were studied in 1) water+propanol/lecithin/hexadecane and 2) ethanol/lecithin/ hexadecane systems. 1) Solvent property of water changes by added alcohol and the hydrophile-lipophile property of lecithin is balanced in 13 wt% propanol aq.-hexadecane system. Three liquid phases, i.e. aqueous alcohol, lecithin and hexadecane are found. The volume fraction of the lecithin phase increases with its concentration and at 2.3 wt%/system, all solvent molecules are swelled and one microemulsion phase is obtained. 2) In ethanol/ lecithin/hexadecane system, lecithin is also insoluble in the solvent, and swells a large amount of hexadecane. 相似文献
24.
Kohei Matsuzaki Kenta Okuyama Etsuko Tokunaga Motoo Shiro Norio Shibata 《ChemistryOpen》2014,3(6):233-237
A sterically demanding unsymmetrical pentafluorophenyl-triisopropylphenyl-λ3-iodane was developed as an effective reagent for the electrophilic pentafluorophenylation of various β-keto esters and a β-keto amide. 17 examples of α-pentafluorophenylated 1,3-dicarbonyl compounds 3 having a quaternary carbon center are provided. The resulting compounds were nicely transformed into chiral α-pentafluorophenyl ketones with an all-carbon stereogenic center in high yields and high enantioselectivities using asymmetric organocatalysis (up to 98 % ee) or asymmetric metal catalysis (up to 82 % ee). 相似文献
25.
A Cu-TiC alloy, with nanoscale TiC particles highly dispersed in the submicron-grained Cu matrix, was manufactured by a self-developed two-step ball-milling process on Cu, Ti and C powders. The thermostability of the composite was evaluated by high-temperature isothermal annealing treatments, with temperatures ranging from 727 to 1273 K. The semicoherent nanoscale TiC particles with Cu matrix, mainly located along the grain boundaries, were found to exhibit the promising trait of blocking grain boundary migrations, which leads to a super-stabilized microstructures up to approximately the melting point of copper (1223 K). Furthermore, the Cu-TiC alloys after annealing at 1323 K showed a slight decrease in Vickers hardness as well as the duplex microstructure due to selective grain growth, which were discussed in terms of hardness contributions from various mechanisms. 相似文献
26.
We investigated the fluorescent properties, including the excited-state intermolecular proton transfer, of urea derivatives comprising a coumarin ring, which is a widely used fluorophore. We prepared two different coumarin–urea derivatives, 6CU and 7CU, which bear a urea-based substituent at the 6 and 7 positions of a coumarin ring, respectively. In the presence of the acetate ion, 7CU showed additional tautomer fluorescence emission with respect to 6CU, indicating that tautomer formation depends on the positions of the urea-based substituent on the coumarin ring. Thus, the resonance structures of urea derivatives might play an important role in the behavior of dual fluorescence, which is an important phenomenon applicable to photochemical anion sensing. Moreover, in order to further improve the fluorescence properties of the mentioned derivatives, a CF3 group was introduced in a phenyl ring opposite to a coumarin ring. The fluorescence quantum yield of 7CUCF3 thus synthesized was 65 times as large as that of 7CU, an observation that renders 7CUCF3 a suitable anion sensor candidate. The results of this study will contribute to the development of new molecular designs for highly fluorescent sensing. 相似文献
27.
We present the validity of in-line-type differential push-pull methods using segmented gratings with respect to arrangement
errors by numerical calculation for the first time. In these differential push-pull methods, the segmented gratings for generating
subspots are divided into more than two regions, each with a specific width and a specific phase value, and are ideally arranged
on the optical axis. We calculate tracking error signals in these methods with respect to the arrangement errors against the
optical axis under parameter conditions of the widths of the segmented regions of the gratings. The obtained results show
that the grating with a simpler configuration with two regions reveals good compatibility between DVD-recordable (DVD-R) and
DVD-random access memory (DVD-RAM) compared with those with three or four regions, when the arrangement error is less than
10% of the radius of the incident laser beam. 相似文献
28.
Ryuichi Kusaka Shohei Ohgi Kenta Shigemori Tetsuya Fujimoto 《Physical Therapy Research》2008,11(1):15-21
The aims of this study were to analyze 1) whether there was the relationship between the neonatal behavioral characteristics and amount of crying in premature infants at term age, and 2) what kind of difference between infants with high levels of crying and cry less on neonatal behavioral characteristics using the Neonatal Behavioral Assessment Scale (NBAS). The study participants consisted of 69 healthy low birth-weight infants who were admitted to the NICU at the Nagasaki University Hospital, Nagasaki, Japan. This study analyzed the relationship between NBAS scores measured neonatal behavioral performance and crying at term age. This study results indicate that there was significant statistical negative correlation between the amount of total daily crying and Habituation, Range of state, Regulation of state, and Autonomic stability cluster scores and some individual items scores (Response decrement to light, Response decrement to tactile of foot, Alert responsiveness, Examiner persistence, Motor maturity, Irritability, General irritability, Cuddliness, Consolability, Self-quieting activity, and State regulation). The high levels crying group also showed higher responsivity than less crying group in the items of Peak of excitement, Rapidity of build-up, Irritability and General irritability. In conclusion, neonatal behavioral characteristics such as poor inhibit discrete stimuli while asleep, hyper-responsivity and poor state regulation abilities were risk factors of high levels of crying. 相似文献
29.
Tamejiro Hiyama Hiroyuki Saimoto Koji Nishio Masaki Shinoda Hajime Yamamoto Hitosi Nozaki 《Tetrahedron letters》1979,20(22):2043-2046
A new method is reported for constructing α-methylene-γ-butyrolactone moiety under neutral, anhydrous conditions. Olefin-dibromocarbene adducts are transformed to methyl 1-(N,N-dimethylaminomethyl)cyclopropanecarboxylates which in turn are treated with trimethylsilyl iodide and the crude products distilled to give the title compounds with high regio- and stereoselectivity. 相似文献
30.
The border luminance of the test stimulus between the natural and unnatural object color, yynBu was obtained for different spatial sizes of the immediate surround to prove that nBu can be determined based on a new recognized visual space of illumination (RVSI) that is assumed to be constructed for the immediate surround separately from the RVSI for the subjects room itself. The nBu of five test stimuli were determined for six different sizes covering from zero to 1866 cm2 with four different lightnesses, N4, N6 and N8, while keeping the room illuminance constant at 100 or 600 lx. The results showed that luminance of the border nBu gradually decreased as the size of the immediate surround was increased and that the decrease was larger for immediate surround with lower lightness. The results were interpreted as showing a new RVSI constructed for the spatial extent of the immediate surround of the test stimulus, and the RVSI was more completely constructed for larger spatial size of the immediate surround. © 2005 The Optical Society of Japan 相似文献