Stretched silver island multilayers have been investigated for patterned optical polarizers for the wavelength of 800 nm. Submicrometer-thick optical polarizing films are fabricated by stretching periodic multilayers consisting of silver island layers and Pyrex layers at the temperature of 660°C. As the optical anisotropy of the optical polarizing film is lost by heating at a temperature higher than the stretching temperature, the fine non-polarizing areas can be deliberately and easily formed on the optical polarizing film by laser irradiation with high power density. We have successfully formed various non-polarizing areas on the optical polarizing film with a 1 W-class carbon dioxide laser. The demonstrated fabricating techniques of deliberately patterned optical polarizing films should be useful for novel optical computing and sensing devices. 相似文献
A new method is proposed for fabricating polymer-coated silver hollow glass fibers to avoid the flexibility deterioration after the curing process. Transmission properties of fibers made by the two procedures with and without curing process are compared. Little difference was observed in the transmission properties at the wavelength 2.94 μm of Er:YAG laser light and 10.6 μm of CO2 laser light. The polymer layer is shown to be stable after 2-h, 5-W, continuous wave CO2 laser light transmission. 相似文献
1,3‐Disubstituted chiral allenes without any heteroatoms act as chiral initiators in the addition of (i‐Pr)2Zn to pyrimidine‐5‐carbaldehyde to afford, in combination with the subsequent asymmetric autocatalysis, chiral pyrimidin‐5‐yl alkanols with up to 98% ee. The absolute configuration of the pyrimidin‐5‐yl alkanol formed depend on that of the chiral allene. 相似文献
In the rac isomer of the title compound, C34H28O2, the two C—Phdimethylphenyl bond axes make an angle of 58.7 (1)°. There is no short contact between the two 3,5‐dimethylphenyl rings, although the dihedral angle between them is 4.93 (7)°. The meso isomer has a center of symmetry at the middle of the C=C bond, and the two C—Phdimethylphenyl bond axes are antiparallel to one another. 相似文献
Porphyrin–AuIII complexes, which were partially or totally modified with C6F5 at the meso positions, were synthesized. The highly electron‐withdrawing substituents induced electron‐deficient states and Lewis acid properties. Single‐crystal X‐ray analysis of the ion pairs revealed ion‐pairing assemblies with characteristics dependent on the number and substitution pattern of the C6F5 units and the geometries of the anions. 相似文献
We carried out a small-angle neutron scattering (SANS) study of dynamically polarized polyethylene (PE) samples doped with 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO). The transmission of the PE with almost fully polarized neutrons (98.5%) increased with increasing the proton polarization, P. The incoherent scattering cross section decreased with increasing P. The effect of P on the polarized neutrons’ transmission and the incoherent scattering cross section agreed well with the theory. The q-dependence of the coherent scattering, which reflects a two-phase structure of PE composed of crystalline and amorphous domains, was kept unchanged by the proton polarization, but the intensity increased by a factor of 3 and 6 for P=+23% and −23%, respectively. The results mean that the contrast between the two phases was successfully enhanced by a dynamic nuclear polarization (DNP) technique. However, the enhancement is only 1/13–1/16 of the enhancement calculated by assuming a homogeneous polarization through the PE sample. The discrepancy suggests that P in amorphous domains (25%) should be higher than that in crystalline domains (22%) by 3%, which in turn may suggest the partial depolarization of proton spins on the way of the spin diffusion from amorphous domains, where TEMPO radicals localize, to crystalline domains. 相似文献
Throw your hat in the ring : A highly diastereoselective synthesis of the ABC rings of (?)‐norzoanthamine has been achieved starting from the (?)‐Hajos–Parrish ketone (see scheme). Three asymmetric quaternary carbon centers on the C ring were constructed by a 1,4‐addition, and an intramolecular Diels–Alder reaction provided a trans‐decalin scaffold on the AB rings.
On solid ground : A new solid‐phase synthesis of N‐linked glycans featuring 1) highly stereoselective β‐mannosylation and microfluidic α‐sialylation and 2) efficient glycosylation of the N‐phenyltrifluoroacetimidate units on JandaJel resin is reported. Reagent concentration effects by a fluorous solvent are effectively applied, and the use of these methods results in the first synthesis of a sialic acid containing complex‐type N‐glycan on a solid support.
Let K be either the rational number field
\Bbb Q{\Bbb Q} or an imaginary quadratic field. We give irrationality results for the number q = ?n=1¥rn/(qn-rl)\theta=\sum_{n=1}^{\infty}{r^n}/(q^n-r^l), where q (∣q∣ > 1) is an integer in K, r∈ K× (∣r∣ < ∣q∣), and
1 £ l ? \Bbb Z1\le l\in{\Bbb Z} with qn ≠ rl (n ≥ 1). 相似文献