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Modern development of flexible electronics has made use of bioelectronic materials as artificial tissue in vivo. As hydrogels are more similar to nerve tissue, functional hydrogels have become a promising candidate for bioelectronics. Meanwhile, interfacing functional hydrogels and living tissues is at the forefront of bioelectronics. The peripheral nerve injury often leads to paralysis, chronic pain, neurologic disorders, and even disability, because it has affected the bioelectrical signal transmission between the brain and the rest of body. Here, a kind of light-stimuli-responsive and stretchable conducting polymer hydrogel (CPH) is developed to explore artificial nerve. The conductivity of CPH can be enhanced when illuminated by near-infrared light, which can promote the conduction of the bioelectrical signal. When CPH is mechanically elongated, it still has high durability of conductivity and, thus, can accommodate unexpected strain of nerve tissues in motion. Thereby, CPH can better serve as an implant of the serious peripheral nerve injury in vivo, especially in the case that the length of the missing nerve exceeds 10 mm.

After a short discussion of various shape memory related phenomena and the basic working mechanisms behind the shape memory effect (SME) in polymeric shape memory materials (SMMs), standard techniques and procedures to characterize these types of materials are reviewed in details (including the concerns in the selection of testing methods and parameters). Although the focus of this paper is on the heating-responsive SME, important issues in the chemo-responsive SME are addressed. Furthermore, some other shape memory related phenomena, such as various kinds of temperature memory effect (TME), and multiple-SME etc., and optimization of the shape memory performance of a shape memory polymer (SMP) via tailoring the programming parameters are included.

Separating the influence of relative density and cell diameter on the tensile properties is very important to the theory research on mechanic properties of microcellular foamed materials. In this article, differences of the influences of relative density and cell diameter on the tensile properties are identified by the foaming PS in constrained mold. The effects of relative density and foaming process conditions such as foaming temperature, foaming time and saturated pressure on the tensile strength and Youngs modulus are analyzed. The results show that relative density is the only structural variable of Youngs modulus and Youngs modulus is not relative to cell diameter. Youngs modulus is in proportion to relative density. Tensile stress of microcellular PS is in contrast to cell diameter, decreases with increasing foaming time and foaming temperature and increases with saturated pressure.

The incorporation of carbon nanofibers with a high aspect ratio and extremely large surface area into glass/epoxy polymers improve their mechanical properties significantly. Previously large number of efforts have been made to improve mechanical properties by mixing carbon nanofibers into resin, however, it may raise high viscosities which create difficulties during manufacturing of polymer composite samples. Presently, an attempt has been made to improve mechanical properties of nanocomposites by using, a different technique i.e spraying the Carbon nanoFibers (CNF) on glass fabric layers before impregnating it with epoxy resin. This paper presents influence of two different processing techniques used for manufacturing of polymer nanocomposites. Firstly, solution was prepared to obtain well dispersed epoxy resin filled with 1.0 wt % CNF, to impregnate carbon fabric in a vacuum assisted resin transfer molding (VARTM) setup for sampling. Secondly, the nanocomposite samples were prepared using a spraying methodology i.e dispersing the CNF solution on carbon fabric and followed by VARTM. Tensile, compression and flexural tests were performed to evaluate the effectiveness of CNF addition on the improvement of mechanical properties by using both techniques. Results indicated, CNF addition offered simultaneous increase in mechanical properties in different percentages by using both the processes respectively. SEM analysis of fractured surfaces has also been carried out to examine the micro structural details of in-depth study.

Carbon nanofibers have been utilized increasingly for enhancing the mechanical properties of advanced polymer composites, which include high strength, stiffness, toughness, and through-thickness Properties. The incorporation of nano particles with a high aspect ratio and extremely large surface area into polymers improves their mechanical properties significantly. Although a number of efforts have been made to improve various properties by mixing nano particles directly into resin, however, it could lead to high viscosities which create problems during processing. In this particular study, an attempt has been made to enhance mechanical response of nano composites by using, state of the art, a different technique i.e spraying the Carbon Nano Fibers (CNF) on dry perform before infusion. The nano composite samples were prepared using a spraying methodology i.e dispersing the 1.0 weight percent CNF solution on carbon fabric, and evaporating the solvent such that only nano fibers remain on perform, followed by Vacuum assisted resin transfer molding (VARTM). Tensile, compression, flexural and short beam strength tests were performed to evaluate the effectiveness of CNF addition on the mechanical properties of carbon / epoxy composites. Results indicated, CNF addition offered simultaneous increase in all these mechanical properties in different percentages i.e 22–28 percent improvement in tensile strength, 7-11 percent in compressive strength, 14–19 percent in Flexural strength and 45-55 percent short beam strength with respect to the neat composite. The rise in their modulus has also been discussed in detail and part of this study. For in-depth analysis, Microscopic approaches were also carried out to investigate the fracture behavior and mechanism of material. Scanning electron microscopy of fractured surfaces revealed improved primary fiber–matrix adhesion and indications of CNF-induced matrix toughening.

The transportation phenomenon of ethanol in pre-deformed poly(methyl methacrylate) (PMMA) is systematically investigated. Two different phenomena simultaneously occur during this process. One is shape recovery, which is resulted from the ethanol induced softening and plasticization of PMMA. The other is swelling, which is produced by the ethanol induced molecular relaxation. Based on this study, a novel surface patterning method is proposed to fabricate PMMA microlens arrays in a simple and cost-effective manner.

Triple-shape memory effect (SME), i.e., to recover the original shape through one intermediate shape upon heating, has been demonstrated as an intrinsic feature of thermo-responsive shape memory polymers (SMPs) after being uniformly programmed, but seemingly has yet been achieved in shape memory alloys (SMAs). In this paper, we study two programming approaches, in which the deformation is uniform throughout the whole sample length without involving any permanent change in material properties at all, to realize the triple-SME in NiTi SMAs. We show that the triple-SME can be tailored to meet the temperature/strain requirements. With this technique, now we are able to achieve step-by-step motion control in SMAs.

Selective enrichment of phosphoproteins or phosphopeptides from complex mixtures is essential for MS-based phosphoproteomics, but still remains a challenge. In this article, we described an unprecedented approach to synthesize magnetic mesoporous Fe3O4@mTiO2microspheres with a well-defined core/shell structure, a pure and highly crystalline TiO2layer, high specific surface area (167.1 m2/g), large pore volume (0.45 cm3/g), appropriate and tunable pore size (8.6–16.4 nm), and high magnetic susceptibility. We investigated the applicability of Fe3O4@mTiO2microspheres in a study of the selective enrichment of phosphopeptides. The experiment results demonstrated that the Fe3O4@mTiO2possessed remarkable selectivity for phosphopeptides even at a very low molar ratio of phosphopeptides/non-phosphopeptides (1:1000), large enrichment capacity (as high as 225 mg/g, over 10 times as that of the Fe3O4@TiO2microspheres), extreme sensitivity (the detection limit was at the fmol level), excellent speed (the enrichment can be completed in less than 5 min), and high recovery of phosphopeptides (as high as 93%). In addition, the high magnetic susceptibility allowed convenient separation of the target peptides by magnetic separation. These outstanding features give the Fe3O4@mTiO2composite microspheres high benefit for mass spectrometric analysis of phosphopeptides.

Solar energy directly converses light energy into DC power without fuel, no moving parts, no pollution, and no noise with long life-span more than about twenty years. Its application is extensive and the set up of solar generation can be scattered and in a small amount on demand which is the most available of all renewable energy, and is the most practical and effective energy. There are many kinds of solar cell, such first generation as Mono-crystalline Silicon, Multi-crystalline Silicon, and Amorphous Silicon, the second generation as Film Photovoltaic and the third generation as Dye-Sensitized (DSSCs) etc. The utilization of solar energy is greatly influenced by environmental change with the main reason of solar radiation. This research collects the data from the test of Mono-crystalline Silicon, Multi-crystalline Silicon, and Film Photovaltaic solar cells in different solar radiation, and then conducts the analysis and research thereby. Using the program written by Labview, collect the data of voltage, current, and the power, solar radiation, and temperature emitted by solar cells under test for analysis. And then discuss the results of the collected data by Matlab for data analysis.

A TiC whisker toughening Al2O3 composite ceramic tool material was developed by an in situ carbothermal reduction synthesis technology. The influence of different synthesis temperatures (1480oC and 1700oC) and holding times (90min, 60min and 30min) on the mechanical properties of the composite was investigated. The results showed that either the lower synthesis temperature (1480oC) or the higher synthesis temperature (1700oC) was necessary to the improvement on the fracture toughness of the composite. However, when an Al2O3-TiO2 eutectic system was formed during the higher temperature synthesis process, grain coarsening of the Al2O3 matrix became much serious, which resulted in obvious decrease in the flexure strength of the composite. Therefore, the carbothermal reduction synthesis process should be divided into two parts including the lower temperature synthesis process for increasing the yield of the TiC whisker and the subsequent higher temperature synthesis process for increasing the carbon content in the TiC whisker, and and the lower temperature synthesis process should be held for enough time (e.g. 60min) to avoid an incomplete carbothermal reduction of TiO2.

A TiC whisker toughening Al2O3-based ceramic cutting tool composite named ATW30 was developed by a two-step in situ synthesis technology. The fracture toughness, flexure strength and Vickers hardness of the composite were 7.63MPa•m1/2, 800MPa and 19.5GPa, respectively. Compared to a (W, Ti)C particle strengthening Al2O3-based ceramic cutting tool composite named SG4, ATW30 was with lower flexure strength and Vickers hardness but much higher flexure strength, and therefore obviously higher wear resistance at either lower or higher cutting speed. The dominant wear mechanism on the flank face of ATW30 is abrasive wear at lower cutting speed and adhesive wear at higher cutting speed. Because of the appearance of the adhesive wear, the wear resistance of ATW30 at higher cutting speed is lower than that of itself at lower cutting speed.

Fabrication of magnetic particles (MPs) with high magnetization and large surface area simultaneously is critical for the application of MPs in bioseparation and drug delivery but remains a challenge. In this article, we describe an unprecedented approach to synthesize mesoporous magnetic colloidal nanocrystal clusters (MCNCs) stabilized by poly(γ-glutamic acid) (PGA) with high magnetization, large surface area (136 m2/g) and pore volume (0.57 cm3/g), excellent colloidal stability, prominent biocompatibility, and acid degradability. This result provides the important step toward the construction of a new family of MCNCs and demonstrates its capacity in a “magnetic motor” drug delivery system. Here, as an example, we explore the applicability of as-prepared mesoporous MCNCs as hydrophobic drug delivery vehicles (paclitaxel as model drug), and the resultant loading capacity is as high as 35.0 wt %. The antitumor efficacy measured by MTT assay is significantly enhanced, compared with free drugs. Thus, combined with their inherent high magnetization, the mesoporous MCNCs pave the way for applying magnetic targeting drug carriers in antitumor therapeutics.

Abstract: The Photovoltaic Array has a best optimal operating point where the array operating can obtain the maximum power. However, the optimal operating point can be compromised by the strength of solar radiation, angle, and by the change of environment and load. Due to the constant changes in these conditions, it has become very difficult to locate the optimal operating point by following a mathematical model. Therefore, this study will focus mostly on the application of Fuzzy Logic Control theory and Three-point Weight Comparison Method in effort to locate the optimal operating point of solar panel and achieve maximum efficiency in power generation. The Three-point Weight Comparison Method is the comparison between the characteristic curves of the voltage of photovoltaic array and output power; it is a rather simple way to track the maximum power. The Fuzzy Logic Control, on the other hand, can be used to solve problems that cannot be effectively dealt with by calculation rules, such as concepts, contemplation, deductive reasoning, and identification. Therefore, this paper uses these two kinds of methods to make_simulation successively. The simulation results show that, the Three-point Comparison Method is more effective under the environment with more frequent change of solar radiation; however, the Fuzzy Logic Control has better tacking efficiency under the environment with violent change of solar radiation.

SiCp reinforced copper matrix composites with the reinforcement content of 30-50vol. % were fabricated by hot pressing using Cu-coated and uncoated SiC powder. And the microstructure and electrical conductivity of the composites were also studied. The results showed that with the increasing of SiCp particle size, the electrical conductivity of the composites also increased. And the oxides in the composites can decrease the electrical conductivity of the composites obviously. The electrical conducting property of the composites can be improved by the copper coating layer and suitable annealing treatment. It provided important data for the application of SiCp/Cu composites as electronic packaging materials.

Weakly ferromagnetic iron oxide nanoparticles with narrow size distribution were prepared by a high-temperature hydrolysis reaction. The magnetic nanoparticles can self-assemble into one-dimensional particle chains on substrates as well as in colloid dispersion through magnetic dipolar interaction without the help of an applied magnetic field. The 1D assemblies were further harnessed to prepare 1D nanostructures with aligned magnetic nanoparticle inclusions and a continuous silica shell. One-dimensional iron oxide/silica nanostructures were prepared through chainlike self-assembly of the magnetic nanoparticles in a mixture of ethanol, ammonia, and water followed by a sol−gel process of TEOS at the surface of the assemblies. The length of the nanostructures can be controlled by the amplitude of ultrasonication, and the thickness of the silica coating can be tuned by the dosage of TEOS. The 1D nanostructures exhibit highly magnetic sensitivity. In the presence of an applied magnetic field, the nanostructures can be oriented and align along the direction of the external magnetic field.

To fabricate ferroelectric ultrathin polymer films with large dielectric constants for potential all‐organic electronic devices, ferroelectric polymer nanotubes and a composite of the nanotubes with a dispersed organic semiconductor have been fabricated by template‐assisted methods. The ferroelectricity drops markedly in spin‐coated ultrathin films less than 100 nm thick, whereas P(VDF‐TrFE) nanotubes with a wall thickness of a few ten nm sustain ferroelectricity. The composite nanotubes exhibit a giant dielectric constant as a result of significantly enhanced interface polarization between the nanosized fillers and the polymer matrix. They could be of practical use in supercapacitors, optoelectronic devices, and sensors.

Conductive nanofibers are adopted to enhance the electric properties of ferroelectric polymers. Polyaniline (PANI) nanofibers doped by protonic acids have a high dispersion stability in vinylidene fluoride‐trifluoroethylene copolymers [P(VDF‐TrFE)] and lead to percolative nanocomposites with enhanced electric responses. About a 50‐fold rise in the dielectric constant of the ferroelectric polymer matrix has been achieved. Percolation thresholds of the nanocomposites are relevant to doping levels of PANI nanofibers and can be as low as 2.9 wt% for fully doped nanofibers. The interface between the conductive nanofiber and the polymer matrix plays a crucial role in the dielectric enhancement of the nanocomposites in the vicinity of the percolation threshold. Compared with other dopants, perfluorosulfonic acid resin is better at improving the performance of the nanofibers in that it serves as a surface passivation layer for the conductive fillers and suppresses leakage current at low frequency. The nanofibers drastically reduce the electric field strength required to switch spontaneous polarization of P(VDF‐TrFE). The nanocomposites can be utilized for potential applications as high energy density capacitors, thin‐film transistors, and non‐volatile ferroelectric memories.

Triple-shape memory effect (SME), i.e., to recover the original shape through one intermediate shape upon heating, has been demonstrated as an intrinsic feature of thermo-responsive shape memory polymers (SMPs) after being uniformly programmed, but seemingly has yet been achieved in shape memory alloys (SMAs). In this paper, we study two programming approaches, in which the deformation is uniform throughout the whole sample length without involving any permanent change in material properties at all, to realize the triple-SME in NiTi SMAs. We show that the triple-SME can be tailored to meet the temperature/strain requirements. With this technique, now we are able to achieve step-by-step motion control in SMAs.

The transportation phenomenon of ethanol in pre-deformed poly(methyl methacrylate) (PMMA) is systematically investigated. Two different phenomena simultaneously occur during this process. One is shape recovery, which is resulted from the ethanol induced softening and plasticization of PMMA. The other is swelling, which is produced by the ethanol induced molecular relaxation. Based on this study, a novel surface patterning method is proposed to fabricate PMMA microlens arrays in a simple and cost-effective manner.

Abstract: Virus-induced gene silencing (VIGS) offers a rapid and high throughput technique platform for the analysis of gene function in plants. Although routinely used in some Solanaceous species, VIGS system has not been well established in Arabidopsis thaliana (L.) Heynh. We have recently reported some factors that potentially influence tobacco rattle virus (TRV)-mediated VIGS of phytoene desaturase (PDS) and actin gene expression in Arabidopsis. In this study, we have further established that the Agrobacterium strain used for agro-inoculation significantly affects the VIGS efficiency. Strain GV3101 was highly effective; C58C1 and LBA4404 were invalid, while EHA105 was plant growth stage-dependent for TRV-induced gene silencing. Furthermore, the VIGS procedure optimised for the PDS gene was applied for the functional analysis of the disease resistance gene RPS2-mediated resistance pathway. Silencing of RPS2 led to loss of resistance to the otherwise avirulence strain of Pseudomonas syringae pv. tomato DC3000 carrying the avirulence gene AvrRpt2. Silencing of RIN4, a RPS2 repressor gene, gave rise to conversion of compatible interaction to incompatible. Silencing of NDR1, RAR1 and HSP90, known to be required for the RPS2-mediated resistance, resulted in loss of the resistance, while silencing of EDS1 and SGT1b, which are not required for the RPS2-mediated resistance, caused no change of the resistance. These results indicate that the optimised procedure for the TRV-based VIGS is a potentially powerful tool for dissecting the signal transduction pathways of disease resistance in Arabidopsis.

A novel, near-monodisperse, well-defined ABA triblock copolymer, poly[2-(dimethylamino)ethyl methacrylate]-b-poly(propylene oxide)-b-poly[2-(dimethylamino)ethyl methacrylate], was synthesized via oxyanion-initiated polymerization. The initiator was a telechelic-type potassium alcoholate prepared from poly(propylene glycol) and KH in dry tetrahydrofuran. The copolymers produced were characterized by Fourier transform infrared, ¹H NMR, and gel permeation chromatography (GPC). GPC and ¹H NMR analyses showed that the products obtained were the desired copolymers, with narrow molecular weight distributions (ca. 1.09–1.11) very close to that of the original poly(propylene glycol). ¹H NMR, surface tension measurements, and dynamic light scattering all indicated that the triblock copolymer led to interesting aqueous solution behaviors, including temperature-induced micellization and very high surface activity. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 624–631, 2002; DOI 10.1002/pola.10144

MCM-41 immobilized heteropoly acids (HPAs) catalysts were synthesized, characterized and their catalytic activities were evaluated in the aza-Michael addition reaction of nitroolefins and benzotriazole in water at room temperature.