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411.
A Spin‐Active,Electrochromic, Solvent‐Free Molecular Liquid Based on Double‐Decker Lutetium Phthalocyanine Bearing Long Branched Alkyl Chains 下载免费PDF全文
Agnieszka Zielinska Dr. Atsuro Takai Dr. Hiroya Sakurai Dr. Akinori Saeki Dr. Marcin Leonowicz Dr. Takashi Nakanishi 《化学:亚洲杂志》2018,13(7):770-774
Synthesis and characterization of a novel, multifunctional, solvent‐free room‐temperature liquid based on alkylated double‐decker lutetium(III) phthalocyanine (Pc2Lu) are described. Lowering of the melting point and viscosity of intrinsically solid Pc2Lu compounds has been achieved through the attachment of flexible, bulky, and long branched‐alkyl chains, that is, thio‐2‐octyldodecyl, to the periphery of the Pc2Lu unit. The embedded Pc2Lu unit maintains its inherent molecular functions, such as spin‐active nature and electrochromic behavior in the liquid state. Comparison of the properties with a solid‐like Pc2Lu derivative, functionalized with shorter alkyl chains, that is, thio‐2‐ethylhexyl, underlines the importance of the hampering effect on the π–π interactions of neighboring Pc2Lu molecules by bulkier and longer branched‐alkyl chains. This study could possibly pave the way for novel multifunctional liquids whose spin‐activities are associated with their rheological or optoelectronic properties. 相似文献
412.
Singh BP Menchavez R Takai C Fuji M Takahashi M 《Journal of colloid and interface science》2005,291(1):181-186
The colloidal stability of suspensions of alumina particles has been investigated by measuring particle size distribution, sedimentation, viscosity, and zeta potential. Alumina particles were found to be optimally dispersed at pH around 3 to 7.8 without dispersant and at pH 8.5 and beyond with dispersant. The above results corroborate zeta potential and viscosity measurement data well. The surface charge of alumina powder changed significantly with anionic polyelectrolyte (ammonium polycarboxylate, APC) and the iep shifted toward more acidic range under different dispersant conditions. It was found that the essential role played by pH and dispersant (APC) on the charge generation and shift in the isoelectric point of alumina manifests two features: (i) the stability decreases on approaching the isoelectric point from either side of pH, and (ii) the maximum instability was found at pH 9.1 for alumina only and at pH 6.8 for alumina/APC, which is close to the isoelectric points for both the system, respectively. Using the model based on the electrical double-layer theory of surfactant adsorption through shift in isoelectric points, the authors could estimate the specific free energy of interaction (7.501 kcal/mol) between particles and dispersant. The interaction energy, zeta potential, sedimentation, and viscosity results, were used to explain the colloidal stability of the suspension. 相似文献
413.
Ho-Hi Lee Kouji Kimura Takatomo Takai Hitoshi Senda Akio kuwae Kazuhiko Hanai 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》1999,55(14):2877
Polymorphs I and II of phenylpyruvic acid are obtained as mixtures of both crystal forms or relatively pure crystals, from different solvents. Polymorph I is more stable than polymorph II at room temperature. Spectral characteristics of these polymorphs are discussed on the basis of IR, Raman and solid state 13C NMR spectra. Also, the assignment of the IR features observed in the 1600–1700 cm−1 region is re-investigated by referring to the spectra of heavy-atom substituted derivatives. It is suggested that the C=O stretching band is split by the crystal field for both polymorphs. 相似文献
414.
Miyazawa T Okabayashi EY Koto F Tanimoto M Okabayashi T 《The Journal of chemical physics》2006,124(22):224321
The millimeter- and submillimeter-wave spectra of the NiI radical in the X (2)Delta(5/2) and A (2)Pi(3/2) states were observed by a source-modulated microwave spectrometer. The NiI radical was generated by a dc glow discharge in the mixture of CH(3)I vapor and Ar gas through the sputtering reaction with a Ni cathode. Observed transition frequencies for each electronic state were independently analyzed using a polynomial energy expression based on Hund's case (c) approximation. The deperturbed rotational constants were also estimated by the perturbation analysis including interaction terms between the ground state and the lowest excited state. 相似文献
415.
Keiji Takai 《Computational Statistics》2012,27(4):701-714
This paper proposes a new step called the P-step to handle the linear or nonlinear equality constraint in addition to the conventional EM algorithm. This new step is easy to implement, first because only the first derivatives of the object function and the constraint function are necessary, and secondly, because the P-step is carried out after the conventional EM algorithm. The estimate sequence produced by our method enjoys a monotonic increase in the observed likelihood function. We apply the P-step in addition to the conventional EM algorithm to the two illustrative examples. The first example has a linear constraint function. The second has a nonlinear constraint function. We show finally that there exists a Kuhn–Tucker vector at the limit point produced by our method. 相似文献
416.
Sato H Sato F Taniguchi M Yamagishi A 《Dalton transactions (Cambridge, England : 2003)》2012,41(6):1709-1712
Vibrational circular dichroism (VCD) spectroscopy was applied to study the stereochemical properties of a star-burst type tetranuclear Ru(III) complex, Δ-(or Λ-)[{Δ-(or Λ-)-Ru(III)(acac)(2)(taet)}(3)Ru(III)] (acac = acetylacetonato; taet = tetraacetylethanato). By comparing the VCD spectra of eight diastereomeric enantiomers, it was shown that the spectra reflected the homo- or hetero-chiral nature of the bridging part connecting the central core and the peripheral region. 相似文献
417.
Statistical properties of the time-averaged speckle-reduced pattern at the image plane of a coherently illuminated uniform diffuse object are theoretically and experimentally studied. The diffuse object is assumed to be approximated by a deep random phase screen and zero-mean circular complex Gaussian statistics is also assumed to hold for the formation of speckles. The time-averaging process is performed by using a rotating aperture at the Fourier transform plane of the object. A theoretical study of the speckle reduction is conducted for a rotating Gaussian soft aperture at the Fourier transform plane. Expressions are analytically derived for the mean, autocorrelation function, power spectrum, and contrast of the time-averaged speckle pattern at the image plane. In particular, the contrast of the time-averaged speckle pattern is theoretically evaluated and its characteristics are discussed in detail. The theoretical results for the contrast are experimentally confirmed using a TV/film recording system. Excellent agreement between theoretical and experimental results is obtained. 相似文献
418.
Maskless etching of Mn-Zn ferrite in dichlorodifluoromethane (CCl2F2) by Ar+-ion laser (514.5 nm line) irradiation has been investigated to obtain high etching rates and aspect-ratio of etched grooves. The etching reaction was found to be thermochemical. High etching rates of up to 360 m/s, which is about one order of magnitude higher than that in a CCl4 gas atmosphere and even higher than that in a H3PO4 solution, have been achieved. A maximum aspect-ratio of 6.9 was obtained. 相似文献
419.
420.
Chika Takai Tadashi Hotta Shuji Shiozaki Shuhei Matsumoto Takehisa Fukui 《Colloids and surfaces. A, Physicochemical and engineering aspects》2011,373(1-3):152-157
A solid-in-oil-in-water (S/O/W) emulsion system has been developed to prepare porous polymeric microspheres. The obtained microspheres showed unique core–shell structure with a dense core and a surface porous layer. The emulsion system has two processes. In the first process, S/O/W1 viscous emulsion is prepared by dropping of S/O phase in the first water phase (W1). In the second process, the S/O/W1 emulsion is poured to another water phase (W2) as S/O/W1/W2 emulsion. During the process, S/O/W1 droplet becomes microsphere after organic medium completely diffusion. Emulsion techniques have various effective combinations such as additive and process conditions to design microsphere morphology. With regards to the proposed S/O/W system, addition of the solid phase in the system is a key factor to form the porous structure. When the medium diffusion starts, the solid makes W1 phase kept inside the S/O/W1 droplet. The remained W1 phase changes surface porous layer after purification. Affinity between the solid and oil phase should be adjusted as well. In this study, an optimization of the emulsion system was attempted considering solubility parameter and polarity. Additionally, it is found that process conditions could help to design microsphere morphology such as pore size and porous layer thickness. 相似文献