Effects of binders on the performance of electric double-layer capacitors of carbon nanotube electrodes

Electric double layer capacitors (EDLCs) or‘su percapacitors’ have many potential advantages inelectrical devices due to their large capacitance, highpower and long cycle life[1,2].Activated carbons, which exhibit a large specificsurface area ( higher than 1000 m2/g), have beenwidely used as polarizable electrodes of the capaci tors[1—3]. However, generally less than 1/3 of thesurface area of these carbons is available to the elec trolyte for the reason that they con…     

Modifying the poly ether ester antistatic agent by carbon nanotubes, the antistatic effect on polypropylene fibers

A new antistatic fiber is investigated using carbon nanotubes (CNTs) to enhance the antistatic ability of polymer fibers based on the mechanism of the discharging process of polarity macromolecule. Composite antistatic agent (CAA), prepared by dispersing CNTs in an organic antistatic agent carrier containing metallic ions in their main chains, is cospun with polypropylene (PP) to prepare CAA/PP fibers. It is indicated through analyzing the measured dynamic tribo-electrostatic voltages that CNTs can promote the discharging process of polarity macromolecule of antistatic agent carrier and further improve the antistatic ability of PP fibers. It is also indicated that the antistatic effect promoted by CNTs is better than that by conductive carbon black. Moreover, the antistatic effects of the CNTs treated by different methods are also compared.     

Effects of biological pre-treatment of pine chips on the beating performance of Kraft pulp

The Calabrien pine (Pinus brutia) wood chips prior to kraft pulping were biologically pre-treated with selected white-rot fungi (Ceriporiopsis subvermispora), which was recorded to be preferentially attacking the lignin component of the wood. The effects of this treatment on beating performance and physical strength of resultant papers were studied in detail. Bio-treated samples showed comparable and, in most cases, higher physico-mechanical properties than those obtained from untreated controls. Under the same beating conditions the bio-treated kraft pulp was noted to have the lower SR° indicating a lower degree of external fibrillation. The paper made from bio-treated kraft pulp has a higher density, tensile property, air permeability and swellability. Furthermore, remarkable energy savings up to 33 % were observed when beating bio-treated kraft pulp. This study contributes to a better understanding of the mechanisms taking place during bio-treatment and the modification processes of cell wall components.     

Experimental investigation of the influence of electric field on frost layer growth under natural convection condition

The influence of direct current (DC) electric field on the thickness and mass of frost on a cold vertical plate was investigated. The photos of frost layer growth were taken with and without the presence of electric field, and results showed that the electric field has a strong influence on the frost thickness. The influences of cold plate temperature and ambient temperature on frost thickness and frost mass were also investigated under the natural convection condition with electric field. Experimental results demonstrated that the cold plate temperature has very strong effect on the frost layer thickness, but its influence on frost mass is minor; the influence of ambient temperature on the frost mass is more obvious than that on the frost thickness.     

Probing the properties of individual nanostructures by novel techniques

Nanomaterials are the fundamental components of nanoscience and nanotechnology, and they are different from bulk materials in grain size, surface/interface-to-volume ratio and grain shape, which are the origins of their unique electrical, optical, thermodynamic, mechanical and chemical properties. The small size of nanostructures hampers the applications of well-established testing and measurement techniques, thus new methods and approaches must be developed for their synthesis, property characterization and device fabrication. This has been the focus of our research, aiming at exploring state-of-the-art techniques for materials processing and characterization. This paper reviews our progress in nanomaterials research.     

Effects of space environment on biological characters of tissue cultured rose seedlings

Tissue cultured rose seedlings were carried into space by SHENZHOU-4 spacecraft and then used as the experimental material to investigate effects of the space environmental conditions on morphology, cytology, physiology and molecular biology of the seedlings. After loaded on the space flight, the plant's height, number of leaves, and fresh weight per seedling were all increased significantly compared to the ground controls. The content of chlorophyll was basically unchanged. In some cells, the ultrastructural changes involved twist, contraction and deformation of cell wall, curvature and loose arrangement of lamellae of some chloroplasts, and a significant increase in number of starch grains per chloroplast. In addition, the number of mitochondria increased, but some mitochondrial outer membrane broke, and some mitochondrial cristae disappeared. The activities of the defense enzymes, such as superoxide dismutase, peroxidase and catalyse, in rose leaves increased and the content of malondialdehyde decreased. In the RAPD analysis with 40 10-mer primers, 36 primers generated 148 DNA bands from both of the space flight treated seedlings and the ground controls, and five primers amplified polymorphic products. The rate of DNA variation was 6.34%.     

Exact n-width on the class of analytic functions in the space of continuous functions

Let ω(·) be a given concave modulus of continuity and ω(g,·) be the modulus of continuity of a function g∈C, where C is the space of 2π-periodic, continuous functions on R with norm ‖f‖C∶=maxt∈R|f(t)|, r,ω∞,β(r=0,1,2,…) denotes those 2π-periodic, real-valued functions f on R that are analytic in the strip Sβ∶=｛z∈C：|Imz|＜β｝, β＞0, and satisfy the restriction condition: ω(f(r),·)≤ω(·). In this paper, the exact n-width of the class of functions r,ω∞,β in the space C is determined.     

Study on the bulk wave radiation of finite-length SAW devices using FEMBEM

Based on the distributions of stress and free charge on the interface of the surface acoustic wave (SAW) device calculated with the combination of boundary element method and finite element method(FEMBEM), the power of each of the three possible bulk waves radiated by the SAW device is calculated, and their contributions to the overall input conductance are separated respectively. Moreover, the formula of angular distributions of their power radiation into the substrate is derived. Consider the effect of mass loading, the resistance density，defined as a scalar, is extended to generalized resistance densities which can be written as three 4×4 tensors and for which the formulas are derived. The bulk wave radiations for a synchronous one-port resonator on 42°Y-rotated LiTaO3 are simulated. It is found that the radiated energy by slow shear wave contributes a very high proportion to input electrical energy in some frequency range.     

Isotopic evolution of the terminal Neoproterozoic and early Cambrian carbon cycle on the northern Yangtze Platform, South China

Profound geotectonic, climatic and biological changes occur during the terminal Neoproterozoic and its transition into the early Cambrian. These are reflected in temporal variations of the chemical and isotopic composition of seawater. We are studying a sequence of sedimentary rocks at the Shatan section, northern Yangtze Platform, Sichuan Province of China. This succession comprises, in ascending stratigraphic order, predominantly calcareous sediments of the Sinian upper Dengying Formation and black shales of the lower Cambrian Guojiaba Formation (time equivalent of Niutitang Fm.). Paleoenvironmental setting represents shallow-water shelf deposits. The objective of our study is to provide temporal records for the isotopic compositions of organic and carbonate carbon throughout this time interval. Organic carbon isotope values display a range between -35.8‰ and -30.1‰ with clear stratigraphic variations. Carbonate carbon isotope data vary between -3.5‰ and +0.5‰. These secular variations are interpreted to reflect perturbations of the global carbon cycle, specifically changes in the fractional burial of organic carbon. However, local conditions have further affected the isotopic signals.     

Interfacial interaction of carbon fiber/PEEK and its effect on the mechanical performance

An in-depth survey of the researches is presented on the anisotropic structure and properties of interphase in carbon fiber reinforced polyetheretherketone composites. The formation and structural nature of interfacial shortrange and long-range effects, micromechanical and macromechanical roles of interphase are discussed. Besides,prospects of further studies and a novel methodology for revealing interfacial properties of thermoplastic composites are demonstrated     

Effects of genistein, daidzein and glycitein on the osteogenic and adipogenic differentiation of bone marrow stromal cells and on the adipogenic trans-differentiation of osteoblasts

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), alkaline phosphatase (ALP) activity and oil red O assays were used to examine the effects of genistein, daidzein and glycitein on the osteogenic and adipogenic differentiation of primary mouse bone marrow stromal cells (MSCs) and the adipogenic trans-differentiation of primary mouse osteoblasts. The results indicated that daidzein, genistein and glycitein at concentrations from 1×10^-8 mol/L to 1×10^-5 mol/L promoted the proliferation of MSCs and osteoblasts; genistein, daidzein and glycitein promoted osteogenic differentiation and inhibited adipogenic differentiation of MSCs, and inhibited adipocytic transdifferentiation of osteoblasts at appropriate concentrations as 17β-estradiol. It suggests that genistein, daidzein and glycitein regulate a dual differentiational process of MSCs into the osteogenic and adipogenic lineages, and trans-differentiational process of primary osteoblasts into the adipocyte lineages, causing a lineage shift toward osteoblast. Protective effects of them on bone may be mediated by a reversal of adipogenesis which may promote the proliferation, differentiation and mineralization of osteoblasts, and make adipocytes secrete less cytokines which may promote osteoclast formation and activation. In addition, the results also indicated that genistein, daidzein and glycitein may be helpful in preventing the development of steroid induced osteonecrosis.     

Effects of solar ultraviolet radiation on the photochemical efficiency, photosynthetic pigments and biomass production of Spirulina platensis

Effects of solar ultraviolet radiation (UVR) on Spirulina platensis were studied by investigating its photochemical efficiency, photosynthetic pigments and biomass production while exposed to full spectrum solar radiation or depleted of UVR for understanding how and to what extent UVR influences its photosynthe tic physiology and production. It was found that UVR brought about an extra inhibition of photochemical efficiency by 26%—30%. The greatest inhibition of pho tochemical efficiency in S. platensis was observed at noontime, and then recovered to some extent in late afternoon no matter which treatment they were exposed to. The contents of chlorophyll a, phycocyanin and carotenoids increased during initial stage of the exposure, but decreased with elongated exposure. UVR decre ased the biomass yield by about 6%. It indicated that filtering out UVR of solar radiation would raise the productivity of S. platensis, which is an important factor that should be considered in the production.     

Effects of diffusion time and diffusion gradient strength on the mean diffusivity of water molecules in healthy human brain

Diffusion time and diffusion gradient strength are two important parameters of pulsed gradient spin echo (PGSE) that is the most commonly used method in diffusion-weighted magnetic resonance imaging. However, the effects of the diffusion time on the mean diffusivity (MD) in previous studies are controversial. In this study, a new experimental protocol was designed to evaluate the effects of the two parameters on the results of PGSE. It was found that MD decreased significantly with the increased diffusion time or increased diffusion gradient strength, which cannot be explained by the previous theories. Through theoretical analysis, we found the flaw in the pulsed gradient spin echo (PGSE) method, which is the explanation for the controversial results of diffusion time obtained by others.