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951.
The interior Radon transform arises from a limited data problem in computerized tomography. The corresponding operator R is
investigated as a mapping between wightedL
2-spaces. Our result is the explicit construction of a singular value decomposition for R. This immediately leads to an inversion
formula by series expansion and range characterizations.
Foundation item: Supported by the Foundation of the Ministry of Education of China and the Science Foundation of Wuhan University
Biography: WANG Jin-ping (1963-), male, Ph.D candidate, Research interests are in numerical solution of singular integral
equation and integral transformation. 相似文献
952.
Two new sorts of fiber optic sensor are designed.Firstly, the variation of refractive index of resin surrounding the embedded fiber optic was mean to observed by measuring the speckle spatial spectrum at the end-face of the fiber optic.Secondly, it is proposed to measuring the change of thickness of the laminate by using fiber optic microbend attenuation.The experiment results measured by the fiber optic sensors are given.The first sort of sensor was found to be able to detect the viscosity process of the resin matrix during cure process includeing the minimum point of viscosity, the gelation point and the end point of cure process; the second sort of sensor could detect the course of change of the thickness of composite laminate pressed by operation pressure.It is benefit for us to optimize the operation technology and to establish the intelligent monitoring system about curing process of composites for the reason that the viscosity process and the change course of the thickness of laminate can be monitored. 相似文献
953.
Research on Chemical Intermediates - Over the past few decades, self-healing materials derived from chitosan have attracted a great deal of attention due to their excellent physical and biological... 相似文献
954.
5-Thio-D-galactopyranose has been synthesized from diacetone galactofuranose in nine steps and 13.4% overall yield. The key step involved a successful conversion of furanosyl 5,6-epoxide with an L-altrose configuration into the corresponding 5,6-thiirane D-galactose derivative, which was hydrolyzed to the target compound. 相似文献
955.
Malgorzata Basko Melania Bednarek Leen Billiet Przemyslaw Kubisa Eric Goethals Filip Du Prez 《Journal of polymer science. Part A, Polymer chemistry》2011,49(7):1597-1604
A straightforward strategy for the synthesis and functionalization of polyurethanes (PUs) via the use of alkyne‐functionalized polytetrahydrofuran (PTHF) diols is described. The alkyne groups have been introduced into the PTHF chains by the cationic ring‐opening copolymerization of tetrahydrofuran and glycidyl propargyl ether. These PTHF prepolymers were combined with 1,4‐butanediol and hexamethylene diisocyanate for the synthesis of linear PUs with latent functionalization sites. The polyether segments of the PUs have then been coupled with several types of functionalized azides by the copper‐catalyzed azide‐alkyne “click” chemistry, for example with phosphonium containing azides for their antibacterial properties. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
956.
Classical molecular dynamics simulations were carried out to investigate the hydrophilic to hydrophobic transition of PNIPAM‐co‐PEGMA close to its lower critical solution temperature (LCST) in 1 M NaCl solution. PNIPAM‐co‐PEGMA is a copolymer of poly(N‐isopropylacrylamide) (PNIPAM) and poly(ethylene glycol) methacrylate (PEGMA). The copolymer consists of 38 monomer units of NIPAM with two PEGMA chains attached to the PNIAPM backbone. The PNIPAM‐co‐PEGMA was observed to go through the hydrophilic?hydrophobic conformational change for simulations at temperature slightly above its LCST. Na+ ions were found to bind strongly and directly with amide O, even more strongly with the O atoms on PEGAMS chains, whereas Cl? ions only exhibit weak interaction with the polymer. Significantly a novel caged stable metal‐organic complex involving a Na+ ion coordinated by six O atoms from the copolymer was observed after the PNIPAM‐co‐PEGMA copolymer went through conformational transition to form a hydrophobic folded structure. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 相似文献
957.
Du‐Qiang Luo Hui‐Ying Deng Xiao‐Long Yang Bao‐Zhong Shi Jing‐Ze Zhang 《Helvetica chimica acta》2011,94(6):1041-1047
Three new triterpenoid derivatives, named (15α)‐15‐hydroxysoyasapogenol B ( 1 ), (7β,15α)‐7,15‐dihydroxysoyasapogenol B ( 2 ), and (7β)‐7,29‐dihydroxysoyasapogenol B ( 3 ), were isolated from cultures of the plant endophytic fungus Pestalotiopsis clavispora. Their structures and relative configurations were elucidated by extensive spectroscopic analysis and X‐ray crystallography. 相似文献
958.
959.
Dmitar Zori? Du?an Lazar Ognjen Rudi? Miroslava Radeka Jonjaua Ranogajec Helena Hir?enberger 《Journal of Thermal Analysis and Calorimetry》2012,110(1):489-495
The article presents the results of physical and chemical properties of lightweight aggregates (LWA) obtained by the thermal treatments of raw composition based on fly ash, supplied by electric plants from Serbia. The production process of LWA consists of raw material preparation, plastic shaping?Cextrusion, granulation, and thermal treatment at three temperatures: 1100, 1150, and 1200?°C. The final firing temperature (T?=?1150?°C) is chosen based on the mechanical and physical properties of the designed aggregates. The particle-size distribution of the LWAs is unimodal (d????16?mm) while the density value varies from 0.98 to 1.99?g/cm3. The water absorption values are determined by use of two methods: 24?h of soaking in cold water and 5?h of boiling. The thermal conductivity of unbound, fired LWA particles is determined by measuring the amount of axially transferred heat in the stationary state. The obtained value of the LWA thermal conductivity (???=?0.0872?W/mK, T?=?1150?°C) is suitable for the production of structural concrete blocks with improved thermal insulating properties. Because of their high-porosity and -compressive strength values, the designed LWA could be used instead of the conventional aggregates in the production of concrete blocks. Consequently, a real valorization of the waste material such as fly ash in Serbia was established. 相似文献
960.
Huijun Jiang Chong Du Zhiqing Zou Xiaowei Li Daniel L. Akins Hui Yang 《Journal of Solid State Electrochemistry》2009,13(5):791-798
One-step, diameter-selective dispersion of single-walled carbon nanotubes (SWCNTs) has been accomplished through noncovalent
complexation of the nanotubes with a water-soluble, biocompatible polymer chitosan at room temperature. Such chitosan-wrapped
individual SWCNTs can be used for the immobilization of horseradish peroxidase (HRP) and be used to construct an electrode
for direct bioelectrochemical sensing without an electron mediator. The direct electron transfer between HRP and the electrode
surface was observed with a formal potential of approximately −0.35 V (vs. saturated calomel electrode) in phosphate buffer
solution and the calculated heterogeneous electron transfer rate constant is approximately 23.5 s−1. Experimental results indicate that the immobilized HRP retains its catalytic activity for the reduction of nitric oxide.
Such an HRP–SWCNT–chitosan-based biosensor exhibited a rapid response time of less than 6 s and a good linear detection range
for nitrite concentration, from 25 to 300 μM with a detection limit of 3 μM. The apparent Michaelis–Menten constant (K
m) and the maximum electrode sensitivity (imax/K
m) are found to be 7.0 mM and 0.16 μA mM−1, respectively. Both the unique electrical properties of SWCNTs and biocompatibility of chitosan enable the construction of
an excellent biosensing platform for improved electrocatalysis of HRP, allowing, specifically, the detection of trace levels
of nitric oxide. 相似文献