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111.
Electrical fields induce a shift towards lower frequencies of the absorption spectrum of mylar, this shift, proportional to the square of the field, is three orders of magnitude smaller than a typical Franz-Keldysh effect and is sensitive to the relative orientation of the static field with respect to the polarization vector of the light. We suggest that the measured shift is mostly due to Stark effects in this amorphous material. This kind of measurement could be used to estimate the degree of crystalline order in partially amorphous solids. 相似文献
112.
Synthesis of optically active natural carotenoids and structurally related compounds. III. Synthesis of (+)-abscisic acid, (?)-xanthoxin, (?)-loliolide, (?)-actinidiolide, and (?)-dihydroactinidiolide The syntheses of (+)-abscisic acid ( 1 ), (?)-xanthoxin ( 2 ), (?)-loliolide ( 3 ), (?)-actinidiolide ( 4 ), and of (?)-dihydroactinidiolide ( 5 ) from one common starting material are reported. The syntheses yield also some enantiomeric or diastereomeric analogues. 相似文献
113.
Zusammenfassung Die Ionisation vonPh
3CCl undPh
3CBr durch aprotische Donoren wurde in Nitrobenzol mit Hilfe von Leitfähigkeitsmessungen untersucht. Das Ausmaß der Ionisation ist proportional den Donizitäten. Ausnahmen werden auf sterische Hinderung zurückgeführt. Die Verbindung [Ph
3C·py]+Br– wurde isoliert.
Influence of the donicity of organic solvents on the ionization of triphenylhalomethanes
The ionization ofPh 3CCl andPh 3CBr by aprotic donors was studied conductometrically in nitrobenzene solution. The degree of ionization increases with increasing donicity of the donor except when sterical hindrance is operative. The compound [Ph 3C·py]+Br– was isolated.相似文献
114.
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116.
Carrier injection in Ge at helium temperatures produces radiation characteristic of the electron hole condensate. Time resolved spectra are used to analyze the presence of both condensate and free exciton radiation at high power levels. Device heating is indicated. 相似文献
117.
Zaccarelli E Mayer C Asteriadi A Likos CN Sciortino F Roovers J Iatrou H Hadjichristidis N Tartaglia P Löwen H Vlassopoulos D 《Physical review letters》2005,95(26):268301
We examine the vitrification and melting of asymmetric star polymer mixtures by combining rheological measurements with mode coupling theory. We identify two types of glassy states, a single glass, in which the small component is fluid in the glassy matrix of the big one, and a double glass, in which both components are vitrified. Addition of small-star polymers leads to melting of both glasses, and the melting curve has a nonmonotonic dependence on the star-star size ratio. The phenomenon opens new ways for externally steering the rheological behavior of soft matter systems. 相似文献
118.
Richard E. Crandall Ernst W. Mayer Jason S. Papadopoulos. 《Mathematics of Computation》2003,72(243):1555-1572
We have shown by machine proof that is composite. The rigorous Pépin primality test was performed using independently developed programs running simultaneously on two different, physically separated processors. Each program employed a floating-point, FFT-based discrete weighted transform (DWT) to effect multiplication modulo . The final, respective Pépin residues obtained by these two machines were in complete agreement. Using intermediate residues stored periodically during one of the floating-point runs, a separate algorithm for pure-integer negacyclic convolution verified the result in a ``wavefront' paradigm, by running simultaneously on numerous additional machines, to effect piecewise verification of a saturating set of deterministic links for the Pépin chain. We deposited a final Pépin residue for possible use by future investigators in the event that a proper factor of should be discovered; herein we report the more compact, traditional Selfridge-Hurwitz residues. For the sake of completeness, we also generated a Pépin residue for , and via the Suyama test determined that the known cofactor of this number is composite.
119.
Supershell structure in alkali metal nanowires 总被引:1,自引:0,他引:1
Nanowires are formed by indenting and subsequently retracting two pieces of sodium metal. Their cross section gradually reduces upon retraction and the diameters can be obtained from the conductance. In previous work we have demonstrated that when one constructs a histogram of diameters from large numbers of indentation-retraction cycles such histograms show a periodic pattern of stable nanowire diameters due to shell structure in the conductance modes. Here, we report the observation of a modulation of this periodic pattern, in agreement with predictions of a supershell structure. 相似文献
120.
Physical mechanisms and a mathematical model are proposed to describe the smoothing of the microrelief of an irradiated surface. Before melting, smoothing is caused by elastoplastic deformation of the material; after the melting of the surface layer of the irradiated target, smoothing is caused by the dynamics of the target boundary under the action of surface tension forces, viscous forces, and inertial forces. The results of numerical simulation agree qualitatively and quantitatively with experimental data. The proposed mathematical model can be used to predict changes in the microrelief of the irradiated surface and to choose irradiation conditions when solving the problems of radiation technologies. 相似文献