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991.
T. Bezrodna I. Chashechnikova L. Dolgov G. Puchkovska Ye. Shaydyuk N. Lebovka V. Moraru J. Baran H. Ratajczak 《Liquid crystals》2005,32(8):1005-1012
Investigations of montmorillonite (MMT) clay mineral modification effects on electro-optical properties of nanocomposites, based on the nematic liquid crystal 4-pentyl-4'-cyanobiphenyl (5CB) and MMT have been carried out. Only the composite with MMT modified by an organic surface-active substance, dioctadecyldimethylammonium chloride, has been shown to manifest electro-optical memory effect and contrast. A polar dopant (acetone), added to the mixture, significantly increases composite homogeneity. Results of IR spectroscopy measurements lead to the conclusion, that there is a mutual influence of components on each other in organoclay systems, which appears as an alignment of near-surface layers of both the organic and inorganic components of the composite. Due to such interactions these systems show electro-optical contrast and memory effect. A composite with organophobic Na-MMT does not show these electro-optical properties, due to the absence of component interactions, as shown by IR spectroscopic data. 相似文献
992.
It has been recognized for some time that when cost-benefit analysis is applied to irreversible environmental decisions, such as that of developing or preserving wilderness land, there can be an option value associated with the preservation decision, which arises when there is future uncertainty with respect to the benefits of development or preservation. In this paper the provenance of option value is examined and it is shown that an important cause is a special kind of uncertainty, viz. the possibility of reversals in direction of the relative valuations of wilderness land and developed land, a property we refer to as ditonicity. It is shown that the more ditonic the relative valuation process the greater the deviance between the certainty-equivalence development policy and the stochastically optimal one, and thus by implication the greater the option value. In the two cases with zero ditonicity, when relative wilderness valuations always increase or always decrease (even though in a stochastic fashion), there is zero option value. The model used assumes that service flows from wilderness and developed land are size-dependent, with future relative values known only in terms of a stochastic process, which can take jumps up or down of the same proportional size, at random times. Development can be partial or total and can occur in impulses at any time over an infinite time horizon. 相似文献
993.
Norihiro Fukuchi Ye Biqing Yasunori Igasaki Narihiro Yoshida Yuji Kobayashi Tsutomu Hara 《Optical Review》2005,12(5):372-377
We have developed optically-addressed and electrically-addressed liquid crystal spatial phase-only light modulators having
no pixelized structures. We obtained a large depth of phase-only modulation and high diffraction efficiency based on the electro-optical
characteristics of a parallel-aligned nematic liquid crystal. These spatial light modulators (SLM) are of the reflection type,
so there would be a loss of power in the readout light from the half mirror, which was set up so as to separate the incident
and reflected lights. To optimize the characteristics of a reflection type spatial phase-only light modulator, we have proposed
an oblique incident optical readout setup. We have examined the effect of conditions such as the polarization direction and
the incidence angle of the readout light, and the orientation of liquid crystal molecules in the SLM. High diffraction efficiency
close to the theoretical maximum value was obtained by adjusting the above conditions. The simulation analysis can well explain
the experimental results of phase modulation. 相似文献
994.
N. V. Generalova Ye. V. Kovalenko 《Journal of Applied Mathematics and Mechanics》1994,58(6):1069-1078
The contact problem of the frictionless penetration of a punch with strip-shaped section into the surface of a linearly-deformable base protected by a thin elastic layer (covering) of variable thickness, the stiffness of which is comparable to or smaller than that of the supporting elastic body, is investigated. A Fredholm integral equation of the second kind is obtained for the unknown contact pressure with a coefficient in front of the leading term that is a fairly arbitrary function of the longitudinal coordinate. To solve it the Bubnov-Galerkin projection method is used in which the coordinate elements are chosen to be a system of orthogonal polynomials and delta-shaped functions [1, 2] (variational-difference method), together with an algorithm for the required asymptotic expansions [3] when the above-mentioned coefficient is small. In the special case of an elastic half-space protected by a covering of constant thickness, the results obtained are compared with the corresponding characteristics given in [4]. 相似文献
995.
小菜蛾颗粒体病毒DNA用BamHI和XhoI酶切,经0.75%琼脂糖凝胶电泳,分别得到12条带和8条带,平均分子量为113.0kb.用Supercos1Cosmid作载体,将Sau3AI部分消化的PxGV-DNA随机片段插入该载体的BamHI酶切位点,转化于XL1-Blue受体菌,经Amp平板筛选转化子,挑出256个Amp+菌落,以32P-dCTP标记的PxGV-DNA为探针,斑点杂交筛选得到59个阳性重组体,再经电泳检测,得到了59个不同大小的PxGV-DNA片段克隆. 相似文献
996.
The recognition capabilities of two molecular receptors 2,7-di(3′-pyridyl)-1,8-naphthyridine (DPN) and 2,7-di(3′-quinolyl)-1,8-naphthyridine (DQN) toward monosaccharides in chloroform were evaluated. Both DPN and DQN possess a naphthyridine core moiety, in which two pyridinic nitrogen atoms serve as the proton acceptors. Attached to the C2 and C7 positions of naphthyridine are two identical arms, each of which consists of pyridine (DPN) or quinoline (DQN) moiety that also acts as the proton acceptor. The arrangement of hydroxyl groups in monosaccharides offers the proton donors complementary to the proton acceptors of DPN (or DQN) to form a quadruply hydrogen bonds complex. The binding processes were studied by UV-vis, fluorescence and 1H NMR spectrophotometric titrations as well as electrospray ionization mass spectroscopy. The binding strength between DPN (or DQN) and examined monosaccharides was comparable to that for many other hydrogen-bonding host molecules previously reported. 相似文献
997.
Experimental investigation ofd Nd:YAG monolithic nonplanar ring lasers operated at 1123 nm wavelength is presented. Stable single-frequency 1123 nm laser output has been obtained with successful suppression of the strong 1064 nm radiation. Single-frequency output power of 1.25 W is demonstrated with a pump power of 3.98 W at 808 nm, which gives a slope efficiency of 39%. The laser frequency tuning range is over 3 GHz, and the average tuning rate with temperature is -2.6 GHz/ degrees C. A strong iodine absorption line can be covered within the laser frequency tuning range. 相似文献
998.
Tong-Hui Deng Xing-Wei An Zi-Liang Lan Lei Chen Sai-yun Ye Zhi-Rong Zhong 《Annalen der Physik》2023,535(4):2200608
Nonclassical effects in mesoscopic systems have attracted much attention recently. In this paper, it is shown that multiphonon bundle emission can be observed in a strong-coupling cavity optomechanical system. Theoretical analysis shows that when the driving field is adjusted to nth-order sideband excitation, the coupling between the cavity mode and the vibrational mode leads to super-Rabi oscillations, and finally results in an n-phonon bundles emission. Based on the current technology, this process can work in a wide range of parameters. Numerical simulation confirms the validity of the derivation. It is thought that this physical mechanism broadens the applications of cavity optomechanical system in realm of quantum phononics, such as in quantum metrology and phonon laser. 相似文献
999.
A model for dependent default with hyperbolic attenuation effect and valuation of credit default swap 总被引:1,自引:0,他引:1
A hyperbolic function is introduced to reflect the attenuation effect of one firm's default to its partner.If two firms are competitors(copartners),the default inten- sity of one firm will decrease(increase)abruptly when the other firm defaults.As time goes on,the impact will decrease gradually until extinct.In this model,the joint distri- bution and marginal distributions of default times are derived by employing the change of measure,and the fair swap premium of a credit default swap(CDS)can be valued. 相似文献
1000.