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61.
Jürgen Krgel Dmitri O Grigoriev Alexander V Makievski Reinhard Miller Valentin B Fainerman Peter J Wilde Rainer Wüstneck 《Colloids and surfaces. B, Biointerfaces》1999,12(3-6):391-397
Π/A isotherms of spread β-lactoglobulin and β-casein at the air–water interface are measured under different spreading conditions. While the isotherms do not show drastic effects of the spreading concentration and the compression rate the interfacial shear rheological behaviour is significantly influenced. In particular, the shear viscosity of β-lactoglobulin layers depend directly on the spreading concentration. Significant viscosity increase is obtained at larger surface pressures when the spreading concentration is increased. In contrast the shear rheology of the spread β-casein layers can be normalised by plotting the viscosities as a function of the surface pressure Π. The different behaviour is discussed in terms of denaturation of the β-lactoglobulin during the monolayer formation process by adsorption from the spread thin protein solution layer. 相似文献
62.
63.
Dianionic Titanyl and Vanadyl (Cation+)2[MIVO(Pc4−)]2− Phthalocyanine Salts Containing Pc4− Macrocycles 下载免费PDF全文
Dr. Dmitri V. Konarev Dr. Alexey V. Kuzmin Dr. Salavat S. Khasanov Alexey L. Litvinov Dr. Akihiro Otsuka Prof. Hideki Yamochi Prof. Hiroshi Kitagawa Prof. Rimma N. Lyubovskaya 《化学:亚洲杂志》2018,13(12):1552-1560
In this study, the titanyl and vanadyl phthalocyanine (Pc) salts (Bu4N+)2[MIVO(Pc4?)]2? (M=Ti, V) and (Bu3MeP+)2[MIVO(Pc4?)]2? (M=Ti, V) with [MIVO(Pc4?)]2? dianions were synthesized and characterized. Reduction of MIVO(Pc2?) carried out with an excess of sodium fluorenone ketyl in the presence of Bu4N+ or Bu3MeP+ is exclusive to the phthalocyanine centers, forming Pc4? species. During reduction, the metal +4 charge did not change, implying that Pc is an non‐innocent ligand. The Pc negative charge increase caused the C?N(pyr) bonds to elongate and the C?N(imine) bonds to alternate, thus increasing the distortion of Pc. Jahn–Teller effects are significant in the [eg(π*)]2 dianion ground state and can additionally distort the Pc macrocycles. Blueshifts of the Soret and Q‐bands were observed in the UV/Vis/NIR when MIVO(Pc2?) was reduced to [MIVO(Pc . 3?)] . ? and [MIVO(Pc4?)]2?. From magnetic measurements, [TiIVO(Pc4?)]2? was found to be diamagnetic and (Bu4N+)2[VIVO(Pc4?)]2? and (Bu3MeP+)2[VIVO(Pc4?)]2? were found to have magnetic moments of 1.72–1.78 μB corresponding to an S=1/2 spin state owing to VIV electron spin. As a result, two latter salts show EPR signals with VIV hyperfine coupling. 相似文献
64.
We present a molecular dynamics simulation study of the crystal growth of methane hydrates in the presence of model silica (SiO(2)) surfaces. The crystal growth under apparent steady-state conditions shows a clear preference for bulk solution. We observe rather disordered water arrangements very close to the silica surface within about 5 ? in both liquid and crystalline regions of the system. These disordered structures have dynamic and structural properties intermediate between those exhibited by molecules in bulk liquid and crystalline phases. The presence of methane molecules appears to help stabilize these structures. We observe that under appropriate conditions, the hydroxylated silica surfaces can serve as a source of methane molecules which can help promote hydrate growth near the surfaces. 相似文献
65.
Competition between lipases and monoglycerides at interfaces 总被引:3,自引:0,他引:3
Reis P Holmberg K Miller R Krägel J Grigoriev DO Leser ME Watzke HJ 《Langmuir : the ACS journal of surfaces and colloids》2008,24(14):7400-7407
Tensiometry (the pendant drop technique), interfacial shear rheology, and ellipsometry have been used to study the effect of polar lipids that are generated during fat digestion on the behavior of lipases at the oil-water interface. Both Sn-1,3 regiospecific and nonregiospecific lipases have been used, and a noncatalytically active protein, beta-lacloglobulin, has been used as reference in the interfacial shear rheology experiments. The results from the pendant drop measurements and the interfacial rheology studies were in agreement with each other and demonstrated that the Sn-2 monoglyceride, which is one of the lipolysis products generated when a Sn-1,3 regiospecific lipase catalyzes triglyceride hydrolysis, is very interfacially active and efficiently expels the enzyme from the interface. Ellipsometry conducted at the liquid-liquid interface showed that the lipase forms a sublayer in the aqueous phase, just beneath the monoglyceride-covered interface. Sn-1/3 monoglycerides do not behave this way because they are rapidly degraded to fatty acid and glycerol and the fatty acid (or the fatty acid salt) does not have enough interfacial activity to expel the lipase from the interface. Since the lipases present in the gastrointestinal tract are highly Sn-1,3 regiospecific, we believe that the results obtained can be transferred to the in vivo situation. The formation of stable and amphiphilic Sn-2 monoglycerides can be seen as a self-regulatory process for fat digestion. 相似文献
66.
Geometric graph composed from a ring and a segment is considered. We deal with the Schrödinger (quantum) and the wave (classical) operators at the edges and the Kirchhoff conditions at the internal vertex. The lengths of the graph edges varies in time. Time evolution of a wave packet is studied in classical and quantum cases. 相似文献
67.
68.
Masanobu Haraguchi David F. P. Pile Toshihiro Okamoto Masuo Fukui Dmitri K. Gramotnev 《Optical Review》2006,13(4):228-230
We have numerically shown the existence of coupled wedge plasmons (CWPs) which propagates along a nano gap of a twin metal
wedge. The CWPs are formed by wedge plasmons which can interact with each other. The dispersion relations of the wavenumber,
propagation distance, and beam area of CWPs, are described and show that the characteristics of CWPs are similar to those
of wedge plasmons and of gap plasmons. We also propose a new plasmon waveguide composed of twin metal wedges with a nano gap. 相似文献
69.
70.
Anomalous absorption of bulk shear sagittal acoustic waves in a layered structure with viscous fluid
It is demonstrated theoretically that the absorptivity of bulk shear sagittal waves by an ultra-thin layer of viscous fluid between two different elastic media has a strong maximum (in some cases as good as 100%) at an optimal layer thickness. This thickness is usually much smaller than the penetration depths and lengths of transverse and longitudinal waves in the fluid. The angular dependencies of the absorptivity are demonstrated to have significant and unusual structure near critical angles of incidence. The effect of non-Newtonian properties and non-uniformities of the fluid layer on the absorptivity is also investigated. In particular, it is shown that the absorption in a thin layer of viscous fluid is much more sensitive to non-zero relaxation time(s) in the fluid layer than the absorption at an isolated solid-fluid interface. 相似文献