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131.
描述不共轴光学系统计算机优化中坐标变换与逆变换、“入瞳”与光线坐标、像面基准与质量函数定义的一致性问题。 相似文献
132.
133.
Transmission electron microscopy of freeze fractured and replicated samples (TEM) and polarizing light microscopy (PLM) are
used to investigate the defect structures of the thermotropic and lyotropic mesophases of the non-steroidal antiinflammatory
drug fenoprofen sodium and of the thermotropic mesophase of the nonionic surfactant sucrose oleate (O1570). All mesophases
have a layered, smectic structure. The thermotropic liquid crystal of feno-profen sodium is an interdigitated smectic A phase
(smectic Ad) having the highest viscosity of the investigated samples. The thermotropic mesophase of the sugar ester is also
of the type smectic A, likely to be of subtype smectic A2 (bilayered smectic structure). The lyotropic mesophase is of lamellar
liquid crystalline nature and has a much lower viscosity than the thermotropic mesophases. In the PLM the lyotropic fenoprofen
mesophase has a strong tendency to form a pseudoisotropic texture, indicating a strong tendency to form undisturbed layered
structures. Other textures exhibited in the PLM are fan-shaped texture and maltese-cross texture. Confocal domains, cylinders,
pits and peaks as well as screw dislocations are found in great number in the TEM. However, no greater regions of undisturbed
lamellar arrangement in the lyotropic mesophase could be detected. The only texture of the thermotropic fenoprofen mesophase
visible in the PLM is the fan-shaped texture, indicating confocal domains as predominant structural elements. However, no
confocal domains (tori or Dupin cyclides) are found in the TEM. In the PLM the sugar–ester mesophase exhibited a fan-shaped
texture, maltese crosses and oily streaks as dominant textures. In the TEM only a few +π and −π disclinations and imperfect
confocal domains could be detected. The discrepancies in the appearance of defect structures and textures between the mesophases
as well as the discrepancies in the findings in the PLM and in the TEM investigations are caused by the different sample preparation
and the different viscosities of the mesophases.
Received: 28 May 1997 Accepted: 2 September 1997 相似文献
134.
QI Yuanhua GUAN Daren & LIU Chengbu . Institute of Theoretical Chemistry Shandong University Jinan China . School of Physics Microelectronics Shandong University Jinan China 《中国科学B辑(英文版)》2006,49(6):492-498
The density functional theory (DFT) combining with the non-equilibrium Green functions (NEGF) method is applied to the study of the electronic transport properties for a Di-thiol-benzene (DTB) molecule coupled to two Au(111) surfaces. The dependence of the transport properties on the bias, the coupling geometry of the molecule-electrode interface, and the intermolecular interaction are examined in detail. The results show that the existence of the hydrogen atom at the end of the DTB molecule would significantly decrease the transmission coefficients, and then the differential conductance (dI/dV). By changing the position of the DTB molecule located between two electrodes a maximum value of calculated current is observed. It is also found that the intermolecular interaction will strongly influence the transport properties of the system studied. 相似文献
135.
Anna B. DenisovaVyacheslav Ya. Sosnovskikh Wim Dehaen Suzanne ToppetLuc Van Meervelt Vasiliy A. Bakulev 《Journal of fluorine chemistry》2002,115(2):183-192
Reaction of 2-hydrazinothiazoles 1 with 1-thienyl- and 1-furyl-1,3-butanediones 2a,b in methanol in the presence of hydrochloric acid mainly leads to a mixture of pyrazoles 3 and pyrazolines 4 or pyrazoles 3 and 5 in strong acidic conditions. Isomeric hydrazones 6 and pyrazolines 4 were formed and isolated in these reactions in the absence of hydrochloric acid. It has been shown that the regioselectivity in the reaction of diketones 2 with hydrazine 1 is governed by both the concentration of acid and the nature of substituents in the 1,3-diketones 2. Cyclization of hydrazones 6 is shown to occur under milder conditions than dehydration for pyrazolines 4. The new heterocyclic compounds were prepared and fully characterized by NMR spectra and by X-ray analysis for 3c. 相似文献
136.
In this study, immunization with a vaccine consisting of multiple F(abt’)2 fragments of affinity-purified antitetanus toxoid antibodies covalently bound to a carrier protein successfully induced antitetanus
toxoid antibodies. Further studies showed that this vaccine preparation contained no biologically detectable tetanus antigen.
The induced antitetanus antibody (Ab1t’) titer was higher than the titer of antibodies binding control antigens. The immunizing
F(abt’)2 preparation did not elicit a secondary antitetanus response from mice primed with tetanus toxoid and, hence, appeared free
of tetanus epitopes. The specificity of Ab1t’ was established by absorption and inhibition with antigen. Immunization with
antitetanus F(abt’)2 (Ab1t’) fragments appears to have elicited naturally occurring autologous antitetanus toxoid antibody (Ab1t’) through an
idiotypic pathway. As predicted by network theory, anti-idiotype (Ab2) and antitetanus (Ab1t’) cycled reciprocally. Clonotypic
characterization of Ab1t’ using isoelectric focusing and affinity immunoblotting showed increases in Ab1t’ titer to be the
result of increased synthesis by limited subsets of antitetanus toxoid B-cell clones and not increased synthesis by multiple
clones, as is characteristic of antigen-driven Ab1 responses. Many Ab1 and Ab1t’ clonotypes had identical pIs, suggesting
that they either share V region genes or are the product of the same B-cell clones. These findings indicate that immunization
with polyclonal multivalent Ab1 preparations can trigger active synthesis of antibodies with the same specificity. The results
provide further evidence for naturally occurring idiotypic cascades that could be exploited for studies of catalytic antibodies. 相似文献
137.
水溶性金属卟啉肿瘤靶向磁共振成像造影剂的研究 总被引:5,自引:0,他引:5
利用显微荧光-阿达玛变换三维图像分析研究了Cu-TSPP,Mn-TSPP,Cu-TMAP,Mn-TMAP4种水溶性金属卟啉人细胞间质进入肿瘤细胞内的富集过程,对金属卟啉的自旋-晶格驰豫性能(R1)的天空结果表明,Mn(Ⅱ)卟啉配合物的R1、值结Gd-DTPA提高1.5-2倍。 相似文献
138.
《Surface and interface analysis : SIA》2003,35(3):282-286
We have developed a high‐speed image processing CCD video camera for real‐time energy‐loss imaging using a conventional electron microscope with an energy‐loss imaging facility. As an initial demonstration of real‐time lock‐in energy‐loss imaging, a background‐subtracted energy‐loss image was observed by attaching the high‐speed image processing CCD video camera to an analytical electron microscope equipped with a floating‐type energy‐loss imaging analyser. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
139.
Teruaki Hayakawa Shin Horiuchi Hiroshi Shimizu Tadashi Kawazoe Motoichi Ohtsu 《Journal of polymer science. Part A, Polymer chemistry》2002,40(14):2406-2414
Polystyrene‐b‐poly(1,2‐isoprene‐ran‐3,4‐isoprene) block copolymers with azobenzene side groups were synthesized by the esterification of azobenzene acid chloride with polystyrene‐b‐hydroxylated poly(1,2‐isoprene‐ran‐3,4‐isopenre) block copolymers for creating new photochromic materials. The resulting block copolymers with azobenzene side groups were characterized for structural, thermal, and morphological properties. IR and NMR spectroscopies confirmed that the polymers obtained had the expected structures. Differential scanning calorimetric measurements by heating runs clearly showed the glass transitions of polystyrene and polyisoprene main chains and two distinct first‐order transitions at temperatures of azobenzene side groups around 48 and 83 °C. The microstructure of these block copolymer films was investigated using both transmission electron microscopy (TEM) and near‐field optical microscopy (NOM). TEM images revealed typical microphase‐separated morphologies such as sphere, cylinder, and lamellar structures. The domain spacing of microphase‐separated cylindrical morphology in the NOM image agreed with that of the TEM results. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2406–2414, 2002 相似文献
140.
Nb4W13O47, a member of the solid solution series Nb8−nW9+nO47 (0?n?5), crystallizes in a threefold superstructure of the tetragonal tungsten bronze structure. While the oxidation of this reduced phase at TOX=1200 °C leads to a separation into the thermodynamically stable phases, lower oxidation temperatures result in products that comprise new structural elements and ordering variants. The characterization of the oxidation products obtained at TOX=1000 °C was performed by scanning transmission electron microscopy applying a high-angle annular dark field detector. At the selected imaging conditions (Z contrast), not only the metal positions are revealed by this technique but valuable additional information about the elemental distribution can be obtained simultaneously. 相似文献