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81.
Cattaneo S Vuorimaa E Lemmetyinen H Kauranen M 《The Journal of chemical physics》2004,120(19):9245-9252
Polarized second-harmonic generation using two fundamental beams, instead of one, offers significant advantages for characterizing nonlinear optical thin films. The technique is more precise and allows the internal consistency of the results to be verified. The superiority of the two-beam arrangement over the traditional single-beam arrangement is demonstrated by determining the susceptibility tensors of Langmuir-Blodgett films. We show that, for a well-understood reference sample, the results obtained using two fundamental beams agree qualitatively with those obtained with a single fundamental beam, but are more precise. In a more complicated situation, however, the single-beam technique appears to work well but yields results that are, in fact, incorrect. The two-beam technique, instead, yields clearly inconsistent results, thereby highlighting systematic errors in the experimental arrangement or in the theoretical model used to interpret the results. 相似文献
82.
The scope and limitations of a tandem 5-exo dig cyclization/Claisen rearrangement sequence involving appropriately substituted 4-alkyn-1-ols as an efficient "one-pot" route to fused tricyclic ring systems is described. The reaction rates were found to be strongly dependent on the nature of the terminal substitutent of the triple bond. In some cases the entire sequence was found to proceed in good yield at temperatures as low as 115 degrees C. 相似文献
83.
We present a highly sensitive nonlinear optical technique to measure optical retardation. The technique is based on second-harmonic generation from thin films using two beams at the fundamental frequency. The sensitive polarization dependence of the process allows measuring optical retardation very precisely. The technique relies on fundamental symmetry principles and does therefore not require complicated experimental arrangement or data analysis. The technique was demonstrated by determining the retardation of a nominal half-wave plate to a precision and repeatability better than lambda/10(4). 相似文献
84.
Raidal M 《Physical review letters》2002,89(23):231803
In left-right models the gluonic penguin contribution to b-->ss;s transition is enhanced by m(t)/m(b) due to the presence of (V+A) currents and by large values of loop functions. Together those effects may overcome the suppression due to the small left-right mixing angle xi less, similar 0.013. Two independent new phases in the B-->phiK(S) decay amplitude appearing in a large class of left-right models can modify the time-dependent CP asymmetry in this decay mode by O(1) and explain the recent BABAR and Belle CP asymmetry measurements in this channel. This scenario implies observable deviations from the standard model also in B(s) decays which could be measured at Tevatron and LHC. 相似文献
85.
Viljo P. HirsjÄrvi Elsa KenttÄmaa Marjatta Suurinkeroinen Berit Aimonen und Rita Martti 《Fresenius' Journal of Analytical Chemistry》1959,171(5):354-359
Zusammenfassung Bei der Durchführung der Fluorbestimmung unter Verwendung der von den Verff. modifizierten Methode von Willard-Winter verursachen die bei den Versuchen angewandten Mengen an Sulfaten, Chloriden oder Orthophosphaten keine Fehler bei der Bestimmung von Milligrammengen an Fluor. Auch der Einflu\ von Boraten, Jodiden und Carbonaten ist so gering, da\ ihnen wenigstens bei den Serienanalysen von Mineralfuttermitteln und Rohphosphaten in den Laboratorien keine Bedeutung zukommt. Demnach braucht man bei den genannten Analysen vor der Destillation keine besonderen Ma\nahmen zu ergreifen, es sei denn, da\ man die Jodide durch Silberperchlorat binden will. Um den geringen Einflu\ der Borate vollstÄndig zu eliminieren, ist es zweckmÄ\ig, die Destillationsdauer etwas zu verlÄngern. 相似文献
86.
The synthesis of novel 4-(phenylethynyl)pyridine subunits containing H2O-soluble complexing agents and their luminescence with EuIII ions are reported. Ligands with high luminescence intensities as well as quantum yields were obtained. Also the prepared labeling reagents as antibody conjugates gave the highest quantum and luminescence yields reported for H2O-soluble EuIII labels. 相似文献
87.
Gerhard Jany Timo Repo Marina Gustafsson Martti Klinga Adnan S. Abu‐Surrah Markku Leskel 《无机化学与普通化学杂志》2000,626(9):1897-1900
The synthesis and characterization of the unsymmetric hafnium dialkyl [1‐(η5‐9‐fluorenyl)‐2‐(η5‐1‐indenyl)ethane]HfCl2 ( 2 ) and corresponding dimethyl complex [1‐(η5‐9‐fluorenyl)‐2‐(η5‐1‐indenyl)ethane]Hf(CH3)2 ( 3 ) is described. The dialkyl hafnocene ( 3 ) crystallizes in monoclinic space group P21/c (No. 14) with a = 9.458(8), b = 8.541(8), c = 23.733(11) Å, β = 93.16(5) deg., V = 1914(3) Å3, Z = 4. Further on, complex 3 was activated with methylaluminiumoxane (MAO) and utilized as a catalyst in ethene polymerization. 相似文献
88.
Ehab M. Al‐Shami Adnan S. Abu‐Surrah Martti Klinga Hamdallah A. Hodali 《无机化学与普通化学杂志》2002,628(6):1433-1436
The phosphorus‐sulfur ligand 1‐(methylthio)‐3‐(diphenylphosphino)‐propane (S‐P3) has been synthesized and characterized by 1H NMR and 13C NMR. Reactions of S‐P3 with [PdCl2(PhCN)2] afforded the complexes [PdCl2(S‐P3)] ( I ) and [PdCl2(S‐P3)2] ( II ), in which S‐P3 acts as a bidentate and monodentate ligand, respectively. Compound I crystallizes in monoclinic space group P21/n (No. 14) with cell dimensions: a = 8.589(3), b = 15.051(3), c = 17.100(3)Å, β = 102.91(2)°, V = 2154.7(9)Å3, Z = 4. Likewise, compound II crystallizes in monoclinic space group P21/n (No. 14) with a = 9.993(5), b = 8.613(4), c = 18.721(5)Å, β = 90.18(3)°, V = 1611.3(12)Å3, Z = 2. Compound II has a trans square planar configuration with only the P‐site of the ligand bonded to the palladium atom. 相似文献
89.
Vinay Kumar Venkata Rajesh Koppolu Douglas Bousfield Martti Toivakka 《Cellulose (London, England)》2017,24(3):1247-1260
Interest in nanocellulose-based coatings for packaging applications has been growing due to their excellent oil and gas barrier properties combined with their sustainable, recyclable, biodegradable, and non-toxic nature. Coating of nanocellulose materials such as microfibrillated cellulose (MFC) on paper/paperboard is challenging compared to traditional paper coating materials due to excessively high viscosity and yield stress of MFC suspensions at rather low solids content, typically below 5%. Possessing large amounts of water and a distinct rheological behavior such suspensions set tough demands on the substrate to be coated. It is important to understand and quantify substrate requirements in order to coat these suspensions successfully and achieve a satisfactory coating quality. A custom-built slot geometry is used herein to enable coating of highly viscous MFC suspensions on different paper-based substrates in a roll-to-roll process. The impact of substrate properties, such as surface chemistry and surface energy, surface roughness and surface porosity, and water absorption capacity on MFC coatability and coating quality is reported. Coating adhesion to the substrate was quantified with surface strength testing of MFC coated substrates. Various techniques, such as Scanning Electron Microscopy, IGT print penetration tests, and air permeability tests were employed for measuring coating coverage and surface porosity. MFC coating was found to adhere best to a highly hydrophilic surface, whereas the most uniform and defect-free film at low coat weights was formed on a smooth surface. It was also found that the MFC coat weight needed for full coverage, and therefore potentially good barrier, needs to exceed the surface roughness volume of the substrate. Water absorption capacity of the substrate also determines the final MFC coating quality obtained. The results clearly highlight the role of paper-based substrate for successful and effective coating of the micro and nanocellulose suspension. 相似文献
90.