Advanced Materials Research Vols. 1004-1005

Abstract:

Abstract: A new bi-capped Keggin heteropoly molybdovanadated derivative, [Co (en)₃]₂[SiMo₈V₆O₄₂]∙6H₂O (1) (en = ethylendiamine) has been hydrothermally synthesized and structurally characterized by the elemental analysis, IR, XPS and single crystal X-ray diffraction. The crystal structure analysis reveals that compound 1 consists of [Co (en)₃]²⁺ transition metal coordination fragment and the [SiMo₈V₆O₄₂]^4- building blocks, which are linked together via hydrogen-bonding interactions to form a new 3-D supramolecular networks.

Abstract: This paper aims to improve the small temperature range and poor heat-conducting property of polyethylene glycol (PEG) in practical use. One side, two different PEGs which have different phase change temperatures are mixed, in order to wider the temperature range; another side, the thermal conductivity was improved by adding graphite into composite. The structure characteristics and thermal property of composite were measured and studied. Thermal infrared imager is used to measure the practical effect of temperature-control, by coating composite on fabrics.

Abstract: In order to improve the filtering effect of the bag filter, ultrafine sea-island fiber nonwovens is used to produce ultra-fine structure dust filter material. At the beginning, sea-island superfine fiber needle-punched nonwoven production technology is introduced. And then testament is made to tensile breaking strength, elongation at break, bursting ,air permeability, capture efficiency of dust with different diameters of 0.3μm, 0.5μm, 1μm and 3μm. At last, the performing difference of the sea-island superfine fiber ultrafiltration bag and its counterpart from the market is compared and analyzed. [1,2] The experimental results showed that the average breaking strength of Sea island superfine fiber ultrafiltration enhancement of non-woven fabric in warp direction is 1931N, its average elongation at break 32.7%, its average of Zonal breaking strength 2561N, its average elongation at break 22.6%, its bursting of average strength 1998.07N, its permeability as high as 428.62×103 m3/s, its filtering precision 82.4% under 0.3μm diameter and 100% under 3μm diameter.

Abstract: In this paper, the influences of different conditions on heat-transfer stability of porous fibrous composition were analyzed by the one-dimensional unsteady heat transfer model. It was resulted that the surface condition of composition was key parameter for heat performance during different thermal process. Great humidity and thermal difference caused the heat transfer fluctuating of material covering, and then changed the thermal conductivity. For the insulation materials under low temperature, the heat performance was sharply fluctuated nearby 0°C.

Abstract: As a natural fiber, kapok fiber has the high hollow degree that is very good for sound absorption. Four different kinds of kapok-based fiber nonwoven fabrics, made by kapok fiber mixing with hollow polyester, viscose fiber, PP fiber and cotton fiber respectively, were made and the sound absorption coefficients were measured in the frequency region of 100 - 6300 Hz by using a two-microphone transfer-function method. The comparisons of the sound absorption for four types of materials with similar thickness and densities with no air gap and with 1 cm, 3 cm air gap were made. The results indicate that the sound absorption of kapok/hollow polyester fiber nonwoven fabrics is superior to those of other three ones and kapok/hollow polyester fiber nonwoven fabrics can be used for sound-absorbing materials in engineering.

Abstract: Bacillus licheniformis HDYM-03 was isolated from flax-retting water. In this research, the production of flax-degumming enzymes by this strain was investigated in four medium, whose sole carbon source was beef extract peptone (BP), pectin (PEC), konjac powder (KGM) and carboxymethylcellulose sodium (CMC), respectively. In PEC medium, the production of pectinase (455.06 U/mL) and polygalacturonase (540.32 U/mL) is higher than that in other medium. In KGM medium, the mannanase reach the highest activity 193.33 U/mL. The production of xylanase and cellulase is extremely lower and could be ignored in all of the four medium. The results show that the production of flax-degumming enzymes by this strain could be significantly induced by flax colloid. B.licheniformis HDYM-03 suggest an applicable potential in flax-retting industry.

Abstract: To determine the the fiber fineness in different parts of the old and young leaves. the pineapple leaf fiber of comte de paris was used as raw material, The results showed that, the length of fiber extracted from the old leaves of comte de paris pineapple ranged from 70 cm to 90 cm, and the average fiber fineness of the the tip and root were 14.13 dtex and 18.50 dtex, respectively. While the length of fiber extracted from the young leaves of comte de paris pineapple ranged from 45 cm to 65 cm, and the average fiber fineness of the the tip and root were 13.09 dtex and 15.03 dtex, respectively. Variance analysis reveals that the fiber fineness of root and tip in the old pineapple leaf showed significant difference (P<0.05) in comte de paris pineapple.

Abstract: Carbon nanotube (CNT) is a new type of nanoscale materials, which has excellent adsorption and mechanical properties. In this paper, carbon nanotubes were added in the regenerated silk fibroin solution to get CNTs/silk fibroin composite fiber, which had more excellent mechanical property than the regenerated fibroin fiber. The results indicate that the optimum preparation conditions are summed up as follows: silk fibroin concentration 35%, spinning temperature 40^oC, carbon nanotube mass fraction 1.0% and the longest storage time less than 7 days. The mechanical property of regenerated fibroin fiber which added with carbon nanotubes is obviously improved.

Abstract: Silicon solar cell surface texture is effective to reduce reflectance and improve light collection. Alkaline etchants is a conventional process of monocrystalline silicon texturing. Isopropyl alcohol (IPA) as buffer solution is expensive and high consumption, which increased the cost of solar cell. In reserch, It has been found that a cheaper surfactant as buffer solution decrease silicon surface interfacial force and increase etchant infiltrating of silicon wafer, so a large number of small and uniform texture appeared on the silicon surface. Pyramids size of about 3μm formed after etching of 15min. A new process to reduce the production cost and form the high quality pyramids texturing has been developed by the investigation.