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排序方式: 共有1185条查询结果,搜索用时 15 毫秒
201.
Yim JH Kim DI Bae JA Park YK Park JH Jeon JK Park SH Song J Kim SS 《Journal of nanoscience and nanotechnology》2011,11(2):1714-1717
Amine-functionalized SBA-15 materials were synthesized by a post synthesis method. Surface area and pore size decreased by attaching functional groups to the pore surface. Furthermore, pore volume was reduced with functionalization. The carbon and nitrogen content gradually increased with the number of amine groups in the silane precursors. Among the amine-functionalized SBA-15 materials, the SBA-15/TMSPDETA showed the highest removal activity given its high reactivity with formaldehyde. 相似文献
202.
Li Y Tao X Chen H Tam WY 《Journal of the Optical Society of America. A, Optics, image science, and vision》2011,28(3):314-317
We report Q-factor enhancement in a one-dimensional (1D) photonic crystal (PC) cavity by embedding electromagnetic-induced-transparency (EIT) planar plasmonic metamaterials in the cavity. Microwave experiments show tenfold Q-factor enhancements, confirming the numerical simulations. More importantly, the Q-factor enhancement is mainly due to both the longitudinal and lateral confinements contributed by the 1D PC cavity and the planar EIT metamaterials, respectively. The combined PC-EIT structure with a prominent cavity figure of merit may find new applications in nonlinear optics, cavity quantum electrodynamics, and low-threshold lasers. 相似文献
203.
204.
Yim CB van der Wildt B Dijkgraaf I Joosten L Eek A Versluis C Rijkers DT Boerman OC Liskamp RM 《Chembiochem : a European journal of chemical biology》2011,12(5):750-760
We report on the SSTR2-binding properties of a series of four dimeric [Tyr3]octreotate analogues with different spacer lengths (nine, 19, 41, and 57 atoms) between the peptides. Two analogues (9 and 57 atoms) were selected as precursors for the design, synthesis, and biological evaluation of DOTA-conjugated dimeric [Tyr3]octreotate analogues for tumor targeting. These compounds were synthesized by using a two-stage click ligation procedure: a Cu(I) -catalyzed 1,3-dipolar cycloaddition ("copper-click" reaction) and a thio acid/sulfonyl azide amidation ("sulfo-click" reaction). The IC(50) values of these DOTA-conjugated [Tyr3]octreotate analogues were comparable, and internalization studies showed that the nine-atom (111) In-DOTA-labeled [Tyr3]octreotate dimer had rapid and high receptor binding. Biodistribution studies with BALB/c nude mice bearing subcutaneous AR42J tumors showed that the (111) In-labeled [Tyr3]octreotate dimer (nine atoms) had a high tumor uptake at 1 h p.i. (38.8 ± 8.3 % ID g(-1) ), and excellent tumor retention at 4 h p.i. (40.9 ± 2.5 % ID g(-1) ). However, the introduction of the extended hydrophilic 57 atoms spacer led to rapid clearance from the circulation; this limited tumor accumulation of the radiotracer (21.4 ± 4.9 % ID g(-1) at 1 h p.i.). These findings provide important insight on dimerization and spacer effects on the in vivo properties of DOTA-conjugated [Tyr3]octreotate dimers. 相似文献
205.
Ju-Young Park Jae-Wook Lee Kyung Hee Park Tae-Young Kim Soon-Ho Yim Xing Guan Zhao Hal-Bon Gu En Mei Jin 《Polymer Bulletin》2013,70(2):507-515
Poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) nanofibers were prepared by the electrospinning method and used as polymer electrolytes in dye-sensitized solar cells (DSSCs). The electrolyte uptake and ionic conductivity of electrospun PVDF-HFP nanofibers with different diameters changed significantly, regardless of the nanofiber thickness. The PVDF-HFP nanofibers prepared from a 15 wt% spinning solution showed high ionic conductivity (1.295 S/cm) and electrolyte uptake (947 %). DSSCs based on the 15 wt% PVDF-HFP nanofiber electrolyte showed an electron transit time of 6.34 × 10?3 s, electronic recombination time of 5.88 × 10?2 s, and conversion efficiency of 3.13 %. Thus, we concluded that the electrospun PVDF-HFP nanofibers can be used as polymer electrolytes in flexible DSSCs as well. 相似文献
206.
207.
Seung-Hee Park Jin-Soo Park Sung-Dae Yim Seok-Hee Park Young-Moo Lee Chang-Soo Kim 《Journal of power sources》2008
Organic/inorganic composite membranes were prepared using two different polymers. BPO4 particles were introduced into polymers via an in situ sol–gel process. Pre-/post-sulfonated polymers were used to prepare composite membranes as matrix. Pre-sulfonated poly(aryl ether ketone) (SPAEK-6F) copolymer was synthesized via nucleophilic aromatic substitution. Degree of sulfonation was adjusted by the percentage of sulfonated monomer. Post-sulfonated poly(ether ether ketone) (SPEEK) was prepared using concentrated sulfuric acid as sulfonation agent. The membranes were characterized in terms of the ion-exchange capacity (IEC), proton conductivity, water uptake, AFM, SEM and their thermal properties. The SPAEK-6F plain membranes showed higher proton conductivity than that of the SPEEK plain membranes at similar water uptake or IEC due to their structural difference. SEM images of the composite membranes showed that the BPO4 particles were homogenously dispersed in the polymer matrices and BPO4 particle size was greatly influenced by polymer matrix. The SPAEK-6F/BPO4 composite membranes had much smaller BPO4 particle size than the SPEEK/BPO4 composite membranes due to well dispersion of BPO4 sol-like particulates in SPAEK-6F polymer solutions forming more hydrophobic/hydrophilic nanophase than SPEEK polymer solutions. The latter containing a few micrometer-scale BPO4 particles showed higher proton conductivity than the former containing hundreds nanometer-scale BPO4 particles at similar water uptake due to the increase in freezable water and effect of particle size. 相似文献
208.
Vessel surface reconstruction with a tubular deformable model 总被引:4,自引:0,他引:4
Yim P.J. Cebral J.J. Mullick R. Marcos H.B. Choyke P.L. 《IEEE transactions on medical imaging》2001,20(12):1411-1421
Three-dimensional (3-D) angiographic methods are gaining acceptance for evaluation of atherosclerotic disease. However, measurement of vessel stenosis from 3-D angiographic methods can be problematic due to limited image resolution and contrast. We present a method for reconstructing vessel surfaces from 3-D angiographic methods that allows for objective measurement of vessel stenosis. The method is a deformable model that employs a tubular coordinate system. Vertex merging is incorporated into the coordinate system to maintain even vertex spacing and to avoid problems of self-intersection of the surface. The deformable model was evaluated on clinical magnetic resonance (MR) images of the carotid (n=6) and renal (n=2) arteries, on an MR image of a physical vascular phantom and on a digital vascular phantom. Only one gross error occurred for all clinical images. All reconstructed surfaces had a realistic, smooth appearance. For all segments of the physical vascular phantom, vessel radii from the surface reconstruction had an error of less than 0.2 of the average voxel dimension. Variability of manual initialization of the deformable model had negligible effect on the measurement of the degree of stenosis of the digital vascular phantom 相似文献
209.
Abnormal loading generated by blast or impact may cause local damage in a building that may evolve to affect the whole structural system. Therefore, structures have to be designed to prevent such disproportional consequences. Connection is an important contributor to ductility and robustness of the structural steel systems in mitigating such consequences. The aim of this study was to derive a better understanding of how steel connections behave under high-speed loads by means of characterizing their resistance, ultimate strength, and ductility in the form of load–impulse diagrams. The established high-strain-rate resistance properties were applied into simplified frame analyses. The accuracy and cost-effectiveness of the approach were then evaluated comparing the results from detailed and simplified models. 相似文献
210.
Eng Leong Tan Soon Yim Tan 《Antennas and Propagation, IEEE Transactions on》2001,49(8):1218-1225
This paper presents a rigorous formulation of the spectral-domain dyadic Green's functions for planar stratified bianisotropic media. The media may consist of any number of layers bounded by optional impedance/admittance walls. Both electric and magnetic dyadic Green's functions for arbitrary field and source locations are derived simultaneously. Based on the principle of scattering superposition, these dyadics are decomposed into unbounded and scattered parts. The scattered dyadic Green's functions are determined without cumbersome operations using the concepts of effective reflection and transmission of outward-bounded and inward-bounded waves. The scattering coefficient matrices are expressed in compact and convenient forms involving global reflection and transmission matrices. Corresponding to the impedance/admittance boundary walls, the global reflection matrices are related directly to the wall impedance/admittance dyadics. For illustration, the general expressions of dyadic Green's functions are applied to the configuration of a grounded bianisotropic slab embedded in isotropic halfspace 相似文献