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111.
112.
Large-aperture liquid crystal (LALC) lens with hole-patterned electrodes possesses small lens power and high addressing voltage because of the thick dielectric layer inserted between the hole-patterned electrode and LC layer. With an embedded narrow floating ring electrode (FRE), the lens power and addressing voltage of the LALC lens could be effectively increased and decreased, respectively. In this study, we analyse the electro-optic performance of LALC lens upon variation of the diameter of the embedded FRE. Results reveal that the FRE diameter determines the electric-field distribution and hence the electro-optic behaviour of the LALC lens. The LALC lens with embedded 2-mm-diameter FRE has excellent lens properties, such as low aberration, high focal quality and modulation transfer function performance comparable with solid glass lens. 相似文献
113.
Hsu‐Feng Lee Po‐Hsun Wang Yi‐Chiang Huang Wen‐Hung Su Ram Gopal Chun Che Lee Steven Holdcroft Wen‐Yao Huang 《Journal of polymer science. Part A, Polymer chemistry》2014,52(18):2579-2587
A series of sterically‐encumbered, sulfonated, poly(arylene ether) copolymers were synthesized and their proton conductivity examined. The series was prepared by copolymerizing a novel monomer, 2″,3″,5″,6″‐tetraphenyl‐[1,1′:4',1″:4″,1″':4″',1″″‐quinquephenyl]‐4,4″″‐diol, with 4,4'‐difluorobenzophenone and bisphenol A. Subsequent sulfonation and solution casting provided membranes possessing ion exchange capacities of 1.9 to 2.7 mmol/g and excellent mechanical properties (Young's modulus, 0.2–1.2 GPa; tensile strength, 35–70 MPa; elongation at break, 62–231%). Water uptake ranged from 34 to 98 wt% at 80 °C/100% RH. Proton conductivities ranged between 0.24 to 16 mS/cm at 80 °C/60% RH, and 3 to 167 mS/cm at 80 °C/95% RH. TEM analysis of the polymers, in the dehydrated state, revealed isolated spherical aggregates of ions, which presumably coalesce when hydrated to provide highly conductive pathways. The strategy of using highly‐encumbered polymer frameworks for the design of mechanically‐robust and dimensionally‐stable proton conducting membranes is demonstrated. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2579‐2587 相似文献
114.
Due to the rapid development and growth of computer networks, there have been greater and greater demands for remote password authentication protocols. Recently, the focus has been on protocols for multiserver environments that run on smart cards. These protocols typically count on the nonce or timestamp to provide protection against the replay attack. However, as Tsaur et al. pointed out, these protocols have some security issues such as disturbance in clock synchronization and vulnerability to the man-in-the-middle attack. In order to solve the above problems, Tsaur et al. proposed a multiserver authentication scheme with key agreement in 2012, and they claimed that their scheme could effectively achieve password-authenticated key agreement while getting around the technical difficulty of implementing clock synchronization in multiserver environments. Unfortunately, we found out that Tsaur et al.’s protocol still has the following weaknesses: (1) inability to resist privileged insider attack, (2) inability to resist known-plaintext attack, (3) inability to provide user anonymity, and (4) lack of perfect forward secrecy. To fix these secure flaws of Tsaur et al.’s protocol, in this paper, we shall propose an improved multiserver authentication protocol with key agreement based on extended chaotic maps. We shall also offer formal proof of smooth execution of the improved authenticated key agreement protocol. 相似文献
115.
116.
The structures of archaeal glycerophospholipids and glycolipids are unique in that they consist of phytanyl substituents ether linked to the glycerol backbone, imparting stability to the molecules. In this contribution, we described multiple-stage linear ion-trap combined with high resolution mass spectrometry toward structural characterization of this lipid family desorbed as lithiated adduct ions or as the [M−H]− and [M−2H]2− ions by ESI. MSn on various forms of the lithiated adduct ions yielded rich structurally informative ions leading to complete structure identification of this lipid family, including the location of the methyl branches of the phytanyl chain. By contrast, structural information deriving from MSn on the [M−H]− and [M−2H]2− ions is not complete. The fragmentation pathways in an ion-trap, including unusual internal loss of glycerol moiety and internal loss of hexose found for this lipid family were proposed. This mass spectrometric approach provides a simple tool to facilitate confident characterization of this unique lipid family. 相似文献
117.
Yih-Shing Duh Jin-Min Yo Wen-Lian Lee Chen-Shan Kao Jing-Ming Hsu 《Journal of Thermal Analysis and Calorimetry》2014,116(1):339-347
Studies on the thermal decompositions of diamyl peroxide (DAPO), dicumyl peroxide (DCPO), and tert-butyl cumyl peroxide (TBCP) were conducted by DSC. Heat of decomposition, exothermic onset point, and chemical kinetics were determined and compared to those data of di-tert-butyl peroxide (DTBP), a model compound for studying thermokinetics of organic peroxide and standardization of a calorimeter. Similarities and differences of decomposition mechanisms between these organic peroxides were proposed and verified. Kinetics on decomposition of uni-molecular reaction via these similar alkoxyl radials accompanying β C–C bond scission were discussed and compared to the results from ab initio calculations. The ranking of thermal stability on dialkyl peroxides is determined to be in the following sequence: DCPO < TBCP < DAPO < DTBP. This rate-determining step in thermal decomposition of dialkyl peroxides possessed an average eigenvalue of log A at about 13.1 ± 1.2. Activation energy on the thermal decomposition of these peroxides was calculated to be 139.5 ± 14.4 kJ mol?1. 相似文献
118.
119.
Amily Fang-ju Jou Chun-Hua Lu Yen-Chuan Ou Shian-Shiang Wang Shih-Lan Hsu Itamar Willner Ja-an Annie Ho 《Chemical science》2015,6(1):659-665
The microRNA, miR-141, is a promising biomarker for prostate cancer. We implement here a two-step sensing platform for the sensitive detection of miR-141. The first step involves the use of semiconductor CdSe/ZnS quantum dots (QDs) modified by FRET quencher-functionalized nucleic acids, that include the recognition sequence for miR-141 and a telomerase primer sequence for the second step of the analytical platform. Subjecting the probe-modified QDs to miR-141, in the presence of duplex specific nuclease, DSN, leads to the formation of a miR-141/probe duplex and to its DSN-mediated cleavage, while regenerating the miR-141. The DSN-induced cleavage of the quencher units leads to the activation of the fluorescence of the QDs, thus allowing the optical detection of miR-141 with a sensitivity corresponding to 1.0 × 10–12 M. The nucleic acid residues associated with the QDs after cleavage of the probe nucleic acids by DSN act as primers for telomerase. The subsequent telomerase/dNTPs-stimulated elongation of the primer units forms G-quadruplex telomer chains. Incorporation of hemin in the resulting G-quadruplex telomer chains yields horseradish peroxidase-mimicking DNAzyme units, that catalyze the generation of chemiluminescence in the presence of luminol/H2O2. The resulting chemiluminescence intensities provide a readout signal for miR-141, DL = 2.8 × 10–13 M. The first step of the sensing platform is non-selective toward miR-141 and the resulting fluorescence may be considered only as an indicator for the existence of miR-141. The second step in the sensing protocol, involving telomerase, provides a selective chemiluminescence signal for the existence of miR-141. The two-step sensing platform is implemented for the analysis of miR-141 in serum samples from healthy individuals and prostate cancer carriers. Impressive discrimination between healthy individuals and prostate cancer carriers is demonstrated. 相似文献
120.
Thermoluminescence response at different irradiation temperatures and photon energies has been studied. Analyses of the glow curve and the peak height of TLD 200, 600, 700 and CaSO4:Dy for irradiations using 60Co, 137Cs and 226Ra were made. 相似文献