Efficient HOG human detection

While Histograms of Oriented Gradients (HOG) plus Support Vector Machine (SVM) (HOG+SVM) is the most successful human detection algorithm, it is time-consuming. This paper proposes two ways to deal with this problem. One way is to reuse the features in blocks to construct the HOG features for intersecting detection windows. Another way is to utilize sub-cell based interpolation to efficiently compute the HOG features for each block. The combination of the two ways results in significant increase in detecting humans-more than five times better. To evaluate the proposed method, we have established a top-view human database. Experimental results on the top-view database and the well-known INRIA data set have demonstrated the effectiveness and efficiency of the proposed method. (C) 2010 Elsevier B.V. All rights reserved.

Layer-by-layer assembly of functional silica and Au nanoparticles for fabricating electrogenerated chemiluminescence sensor

We described the use of silica nanoparticles as building blocks for the immobilization of electrogenerated chemiluminescence (ECL) reagent Ru(bpy)3" and the fabrication of layer-by-layer assembly film by alternating the deposition of the Ru(bpy)3 2'-doped silica nanoparticles and Au nanoparticles.

Research progress on noble metal composite nanoparticles

Noble metal composite nanoparticles, as attractive building blocks of advanced functional materials, have received enormous attentions due to their specific optical, electronic and catalytic properties that are distant from those of the corresponding monometal nanoparticles. Such materials have important applications in such areas as sensors, optical materials, catalysis and biology, and developed into an increasingly important research area in nanomaterials science. This article reviews the recent progress in the synthesis, properties, and applications of noble metal composite nanoparticles with core-shell, heterostructure, and alloy structure.

Crystallization and morphology of poly(ethylene oxide-b-lactide) crystalline-crystalline diblock copolymers

The crystallization behaviors and morphology of asymmetric crystalline-crystalline diblock copolymers poly(ethylene oxide-lactide) (PEO-b-PLLA) were investigated using differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), and microscopic techniques (polarized optical microscopy (POM) and atomic force microscopy (AFM)). Both blocks of PEO5-b-PLLA(16) can be crystallized, which was confirmed by WAXD, while PEO block in PEO5-b-PLLA(30) is difficult to crystallize because of the confinement induced by the high glass transition temperature and crystallization of PLLA block with the microphase separation of the block copolymer.

Self-assembly of rod-coil-rod ABA-type triblock copolymers

Self-assembled behavior of symmetric ABA rod-coil-rod triblock copolymer melts is studied by applying self-consistent-field lattice techniques in three-dimensional space. The phase diagram is constructed to understand the effects of the chain architecture on the self-assembled behavior. Four stable structures are observed for the ABA rod-coil-rod triblock, i.e., spherelike, lamellar, gyroidlike, and cylindrical structures. Different from AB rod-coil diblock and BAB coil-rod-coil triblock copolymers, the lamellar structure observed in ABA rod-coil-rod triblock copolymer melts is not stable for high volume fraction of the rod component (f(rod)=0.8), which is attributed to the intramolecular interactions between the two rod blocks of the polymer chain.

Layer-by-layer assembly of viral capsid for cell adhesion

Cowpea mosaic virus (CPMV)-based thin films are biologically active for cell culture. Using layer-by-layer assembly of CPMV and poly(diallyldimethylammonium chloride), quantitatively scalable biomolecular surfaces were constructed, which were well characterized using quartz crystal microbalance, UV-vis and atomic force microscopy. The surface coverage of CPMV nanoparticles depended on the adsorption time and pH of the virus solution, with a greater amount of CPMV adsorption occurring near its isoelectric point. It was found that the adhesion and proliferation of NIH-3T3 fibroblasts can be controlled by the coverage of viral particles using this multilayer technique.

Tin (IV) phthalocyanine oxide: An air-stable semiconductor with high electron mobility

Air-stable n-type field effect transistors were fabricated with an axially oxygen substituted metal phthalocyanine, tin (IV) phthalocyanine oxide (SnOPc), as active layers. The SnOPc thin films showed highly crystallinity on modified dielectric layer, and the electron field-effect mobility reached 0.44 cm(2) V-1 s(-1). After storage in air for 32 days, the mobility and on/off ratio did not obviously change. The above results also indicated that it is an effective approach of seeking n-type semiconductor by incorporating the appropriate metal connected with electron-withdrawing group into pi-pi conjugated system.

Uniform Colloidal Alkaline Earth Metal Fluoride Nanocrystals: Nonhydrolytic Synthesis and Luminescence Properties

In this paper, we present a facile and general synthetic route to high-quality alkaline earth metal fluoride (AEF(2), AE = Ca, Sr, Ba) nanocrystals and CaF2:Tb3+ nanocrystals based on the thermal decomposition of corresponding trifluoroacetate precursors in hot oleylamine. X-ray diffraction, transmission electron microscopy, thermogravimetric and differential thermal analysis, Fourier transform infrared spectra, photoluminescence spectra, and kinetic decays were employed to characterize the samples. The use of single-source precursors plays an important role in the formation of high-quality AEF(2) nanocrystals, and the formation process is demonstrated in detail.

Construction of coordination networks with high connectivity: a new 8-connected self-penetrating network based on tetranuclear metal clusters

Two highly connected cobalt(II) and zinc(II) coordination polymers with tetranuclear metal clusters as the nodes of network have been prepared, being the first example of an 8-connected self-penetrating net based on a cross-linked alpha-Po subnet.

Phthalocyanato tin(IV) dichloride: An air-stable, high-performance, n-type organic semiconductor with a high field-effect electron mobility

Phthalocyanato tin(IV) dichloride, an axially dichloriniated MPc, is an air-stable high performance n-type organic semiconductor with a field-effect electron mobility of up to 0.30 cm(2) V-1 s(-1). This high mobility together with good device stability and commercial availability makes it a most suitable n-type material for future organic thin-film transistor applications.

Self-Assembled Growth of Agln(MoO4)(2) Submicroplates into Hierarchical Structures and Their Near-Infrared Luminescent Properties

Layer-controlled hierarchical flowerlike AgIn(MoO4)(2) microstructures with "clean" surfaces using submicroplates as building blocks without introducing any template have been fabricated through a low-cost hydrothermal method. The near-infrared luminescence of lanthanide ion (Nd, Er, and Yb) doped AgIn(MoO4)(2) microstructures, in the 1300-1600 nm region, was discussed and is of particular interest for telecommunication applications. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, electron diffraction, and photoluminescence spectra were used to characterize these materials.

Synthesis and characterization of phenylene-thiophene all-conjugated diblock copolymers

Grignard metathesis (GRIM) polymerization for all-conjugated diblock copolymers comprising poly (2,5-dihexyloxy-1,4-phenylene) (PPP) and poly(3-hexylthiophene) (P3HT) blocks were systematically studied with LiCl as additive and 1,2-bis (diphenylphosphino) ethane nickel dichloride (Ni(dppe)Cl-2) or 1,3-bis(diphenylphosphino) propane nickel dichloride (Ni(dppp)Cl-2) as catalyst. It was found that the addition order of the monomers was crucial for the success of copolymerization. With the monomer addition in the order of phenyl and then thienyl Grignard reagents, all-conjugated PPP-b-P3HT diblock copolymers with different block ratios were successfully synthesized. In contrast, the inverted addition order only afforded a mixture containing both block copolymers and deactivated or end-capped homopolymers.

Bump-Surface Multicompartment Micelles from a Linear ABC Triblock Copolymer: A Combination Study by Experiment and Computer Simulation

Novel bump-surface multicompartment micelles formed by a linear amphiphilic ABC triblock copolymer via self-assembly in selective solvent were successfully observed both in simulation and experiment. The results revealed that the block A forms the most inner core, and the blocks B and C form the inner and outer layers, respectively, and the bumps were formed by block A and more likely to be born on curving surfaces. Moreover, the micelle shape could be controlled by changing the solvent selectivity of the blocks A and B. Spherical, cylindrical, and discoidal micelles with bumpy surfaces were obtained both in experiment and simulation.

Simulation Study of Aggregate Morphologies Formed by ABC Linear Triblock Copolymers in a Selective Solvent Through the Self-Consistent Field Theory

The effect of the hydrophobic properties of blocks B and C on the aggregate morphologies formed by ABC linear triblock copolymers in selective solvent was studied through the self-consistent field theory. Five typical micelles, such as core-shell-corona, hamburger-like, segmented-wormlike, were obtained by changing the hydrophobic properties of blocks B and C. The simulation results indicate that the shape and size of micelle are basically controlled by the hydrophobic degree of the middle block B, whereas the type of micelle is mainly determined by the hydrophobic degree of the end block C.

Novel hydrophilic-hydrophobic multiblock copolyimides as proton exchange membranes: Enhancing the proton conductivity

A series of novel multiblock copolymers based on sulfonated copolyimides were developed and evaluated for use as proton exchange membranes (PEMs). In these multiblock copolyimides, the hydrophilic blocks were composed of the sulfonated dianhydride and the sulfonated diamine, with sulfonic acid groups on every aromatic ring (i.e., fully sulfonated). This molecular design was implemented to effectively enhance the proton conductivity. The properties of the multiblock copolyimides with varying IEC values or block lengths were investigated to obtain a better understanding of the relationship between molecular structure and properties of proton exchange membranes. The water uptake and proton conductivity were found to be highly dependent upon their structure. The block copolymers displayed significantly higher proton conductivities, especially at low relative humidity than the random copolymers with a similar IEC.