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141.
In this paper, characteristics of the interface crack-tip stress and electric displacement fields in transversely isotropic piezoelectric bimaterials are studied. The authors have proven, within the framework of the generalized Stroh formalism for piezoelectric bimaterials, that there is no coexistence of the parameters (oscillating) and κ (non-oscillating) in the interface crack-tip generalized stress field for all transversely isotropic piezoelectric bimaterials. This leads to the classification of piezoelectric bimaterials into one group that exhibits the oscillating property in the interface crack-tip generalized stress field and the other that does not. Fifteen (15) pair-combinations of six (6) piezoelectric materials PZT-4, PZT-5H, PZT-6B, PZT-7A, P-7, and BaTiO3, which are commonly used in practice, are numerically analyzed in this study, and the results backup the above theoretical conclusions. Moreover, the associated eigenvectors for such material systems (with either =0 or κ=0) are also obtained numerically, and the result show that there still exist four linear independent associate eigenvectors for each bimaterial. 相似文献
142.
Liwen Hu Fang Wang Nan‐Ning Ou‐Yang Na Gao Qian Gao Tiantian Ge Yanyan Gao Guangcong Liu Yang Zheng Yang Liu 《Photochemistry and photobiology》2014,90(4):925-934
Human outdoor activities are randomly orientated at different angles to the sun. To quantify the ocular UV and biologically effective UV (UVBE; i.e. the ocular UV irradiance exposure for photokeratitis (UVpker), photoconjunctivitis (UVpcon), and cataract (UVcat)) exposure for different rotation angle ranges, a rotating manikin was used to monitor the ocular UV exposure at different rotation angles in clear skies during July 2010 in Sanya, China. As a result, the ocular UV and UVBE irradiance was directly influenced by the rotation angle variations, primarily for the 120° rotation angle ranges facing the morning and afternoon sun when the solar elevation was lower than 60°; during these times, the UV and UVBE spectral irradiance decreased as the rotation angle increased. When compared to the 360° rotation angle ranges (which were considered to be the average exposure situation), the cumulative ocular UVBE for 60°, 120° and 180° rotation angle ranges were maximally 91% (UVcat), 94% (UVpker) and 121% (UVpcon); 71% (UVcat), 74% (UVpker) and 95% (UVpcon); 42%(UVcat), 45%(UVpker) and 55% (UVpcon) higher respectively. Meanwhile, the cumulative ocular UVBE for the 180° rotation angle ranges facing away from the sun were 46% (UVpker), 59% (UVpcon) and 45% (UVcat) lower. 相似文献
143.
A fully integrated polydimethylsiloxane (PDMS)/modified PDMS membrane/SU-8/quartz hybrid chip was developed for protein separation using isoelectric focusing (IEF) mechanism coupled with whole-channel imaging detection (WCID) method. This microfluidic chip integrates three components into one single chip: (i) modified PDMS membranes for separating electrolytes in the reservoirs from the sample in the microchannel and thus reducing pressure disturbance, (ii) SU-8 optical slit to block UV light (below 300?nm) outside the channel aiming to increase detection sensitivity, and (iii) injection and discharge capillaries for continuous operation. Integration of all these components on a single chip is challenging because it requires fabrication techniques for perfect bonding between different materials and is prone to leakage and blockage. This study has addressed all the challenges and presented a fully integrated chip, which is more robust with higher sensitivity than the previously developed IEF chips. This chip was tested by performing protein and pI marker separation. The separation results obtained in this chip were compared with that obtained in commercial cartridges. Side-by-side comparison validated the developed chip and fabrication techniques. 相似文献
144.
145.
Linear fused dithieno[2,3-b:3'2'-d]thiophene diimides (DTTDIs, 1-4) were synthesized. Physicochemical investigations suggested that these diimides might be used as potential n-channel organic semiconductors. Single-crystal analysis of N-propyl DTTDI (1) revealed that molecules adopt a layered herringbone packing motif. 相似文献
146.
Yigui Ou 《Applied Numerical Mathematics》2011,61(7):900-909
This paper presents a hybrid trust region algorithm for unconstrained optimization problems. It can be regarded as a combination of ODE-based methods, line search and trust region techniques. A feature of the proposed method is that at each iteration, a system of linear equations is solved only once to obtain a trial step. Further, when the trial step is not accepted, the method performs an inexact line search along it instead of resolving a new linear system. Under reasonable assumptions, the algorithm is proven to be globally and superlinearly convergent. Numerical results are also reported that show the efficiency of this proposed method. 相似文献
147.
148.
Facile electrochemical synthesis of hexagonal Cu2O nanotube arrays and their application 总被引:1,自引:0,他引:1
Large-scale and highly oriented single-crystalline hexagonal Cu(2)O nanotube arrays have been successfully synthesized using a two-step solution approach, which involves the electrodeposition of oriented Cu(2)O nanorods and a subsequent dissolution technique along the c axis to form a tubular structure. Herein, NH(4)Cl was found to be an effectual additive, and it can successfully realize the dissolution process of Cu(2)O from nanorods to nanotubes. The dissolution mechanism of Cu(2)O from nanorods to nanotubes was illustrated in detail. These prepared Cu(2)O nanotube arrays were characterized by SEM, EDS, XRD, XPS, and TEM. The photoluminescence (PL) spectrum of Cu(2)O nanotube arrays was also measured, and it shows there is a greater fraction of copper or oxygen vacancies in these prepared Cu(2)O nanotubes. Finally, the applications of Cu(2)O nanotube arrays for gas sensors were investigated in this paper. 相似文献
149.
Ou Z Zhu W Fang Y Sintic PJ Khoury T Crossley MJ Kadish KM 《Inorganic chemistry》2011,50(24):12802-12809
The electrochemistry of gold(III) mono- and bis-quinoxalinoporphyrins was examined in CH(2)Cl(2) or PhCN containing 0.1 M tetra-n-butylammonium perchlorate (TBAP) before and after the addition of trifluoroacetic acid to solution. The investigated porphyrins are represented as Au(PQ)PF(6) and Au(QPQ)PF(6), where P is the dianion of the 5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrin and Q is a quinoxaline group fused to a β,β'-pyrrolic position of the porphyrin macrocycle; in Au(QPQ)PF(6) there is a linear arrangement where the quinoxalines are fused to pyrrolic positions that are opposite each other. The porphyrin without the fused quinoxaline groups, Au(P)PF(6), was also investigated under the same solution conditions. In the absence of acid, all three gold(III) porphyrins undergo a single reversible Au(III)/Au(II) process leading to the formation of a Au(II) porphyrin which can be further reduced at more negative potentials to give stepwise the Au(II) porphyrin π-anion radical and dianion, respectively. However, in the presence of acid, the initial Au(III)/Au(II) processes of Au(PQ)PF(6) and Au(QPQ)PF(6) are followed by an internal electron transfer and protonation to regenerate new Au(III) porphyrins assigned as Au(III)(PQH)(+) and Au(III)(QPQH)(+). Both protonated gold(III) quinoxalinoporphyrins then undergo a second Au(III)/Au(II) process at more negative potentials. The electrogenerated monoprotonated monoquinoxalinoporphyrin, Au(II)(PQH), is then further reduced to its π-anion radical and dianion forms, but this is not the case for the monoprotonated bis-quinoxalinoporphyrin, Au(II)(QPQH), which accepts a second proton and is rapidly converted to Au(III)(HQPQH)(+) before undergoing a third Au(III)/Au(II) process to produce Au(II)(HQPQH) as a final product. Thus, Au(P)PF(6) undergoes one metal-centered reduction while Au(PQ)PF(6) and Au(QPQ)PF(6) exhibit two and three Au(III)/Au(II) processes, respectively. These unusual multistep sequential Au(III)/Au(II) processes were monitored by thin-layer spectroelectrochemistry and a reduction/oxidation mechanism for Au(PQ)PF(6) and Au(QPQ)PF(6) in acidic media is proposed. 相似文献
150.
On optimizing edge connectivity of product graphs 总被引:1,自引:0,他引:1
Jianping Ou 《Discrete Mathematics》2011,(6):172
This work studies the super edge connectivity and super restricted edge connectivity of direct product graphs, Cartesian product graphs, strong product graphs and lexicographic product graphs. As a result, sufficient conditions for optimizing the edge connectivity and restricted edge connectivity of these graphs are presented. 相似文献