This study was conducted to verify the effect of an electric pulse on growth of crops (lettuce and hot pepper) that were cultivated in lab-scale soil. The electric pulse generated from direct-circuited 2, 4, 6, 8, and 10 V of electricity by periodic exchange of the anode and cathode was charged to a culture soil that is an electrically pulsed culture soil (EPCS) but not charged to a conventional culture soil (CCS). Growth of lettuce increased and growth duration of hot pepper plants was more prolonged at 4, 6, 8, and 10 V of EPCS than at 2 V of EPCS and CCS. The fruiting duration and yield of hot pepper fruits were proportional to the growth duration of the hot pepper plants. Temperature gradient gel electrophoresis (TGGE) patterns of 16S-rDNA obtained from the bacterial community inhabiting the CCS and EPCS were identical at the initial time and did not change significantly at days 28 and 56 of cultivation. The bacterial communities inhabiting the surface of lettuce roots were not influenced by the electric pulse but were significantly different from those inhabiting the culture soil based on the TGGE patterns. Growth of lettuce and hot pepper plants that were cultivated in 4 - 10 V of EPCS may increase; however, the bacterial community inhabiting the soil and the surface of plant roots may not be influenced by an electric pulse
Ralstonia eutropha was genetically modified to induce ethanol production from glucose. An electrochemical bioreactor was prepared to generate electrochemical reducing power coupled to regeneration of NADH. Growing cells of recombinant R. eutropha produced about 29 mM of ethanol in conventional conditions and 56 mM of ethanol in electrochemically reduced conditions from 100 mM glucose. Grown cells of the recombinant produced about 52 mM of ethanol in conventional conditions and 142 mM of ethanol in electrochemically reduced condition from 100 mM glucose. These results are a clue that electrochemical reducing power can induce the recombinant R. eutropha to produce more ethanol coupled to increase of NADH/NAD + ratio.
Lignocellulose biomass is a kind of rich reserve in china, and it is a renewable bio-resource. Researches on the bioconversion of lignocellulose (lignocellulosic biomass) to ethanol have been hot spot in recent years. The key technologies of producing fuel alcohol by aspects of lignocellulosic raw materials, pretreatment technology, fermentation process, enzymatic hydrolysis and fermentation of strains as well as the removal of fermentation inhibitors have been reviewed. It is pointed out that the improvement of fermentation strains, exploitation of double function saccharomyces cerevisiae (glucose and xylose fermenting) to ethanol, will be the direction and focus in future researches.
The Gd-based amorphous/nanocrystal composite is prepared by controlling the cooling rate and the element ratio. The X-ray diffraction, differential scanning calorimeter and atomic force microscope/magnetic force microscope are used to confirm the composite microstructures from different perspectives. The magnetic test shows the great enhancement of magnetocaloric effect in the metallic glassy composite. The large magnetic refrigerant capacity (RC) up to 103 J. kg-1 is more than double the RC values of the Gd-based bulk metallic glass and pure Gd. The full width at half maximum of the magnetic entropy change (Sm) peak almost spreads over the whole low-temperature range, which is five times wider than that of the pure Gd. The maximum Sm approaches a nearly constant value in a wide temperature span (over 80 K). The super paramagnetic nanoclusters of the composite increase the magnetic refrigerant capacity greatly. In combination with the low magnetic hysteresis and large resistance, the metallic glass composite may be a potential candidate for the ideal Ericsson-cycle magnetic refrigeration.
In this paper, the piezoresistive effect of the multiwalled carbon nanotube (MWCNT) film is studied. Carbon nanotubes are synthesized by hot filament chemical vapor deposition. The piezoresistive effect in the MWCNT film is studied by a three-point bending test. The gauge factor of the MWCNT film under 500 microstrain is found to be at most 120 at room temperature, exceeding that of polycrystalline silicon (30) at 35℃. The origin of the piezoresistivity in MWCNT film is also discussed.
Mechanical properties of micro- and nanoscale fibers are superior to their bulk counterparts, and their mechanical behaviors are different from each other. Homogeneous amorphous fibers with smooth surfaces and controllable sizes can be continuously drawn from supercooled liquid. Compared with the preparing of crystalline fibers, the manufacturing of amorphous fibers saves much energy and time. Furthermore, amorphous materials have excellent mechanical properties due to their short-ranged ordered and long-ranged disordered structures. Therefore, amorphous fibers have wide engineering applications and research interest. In this paper we review the fabrication and mechanical behaviors of amorphous fibers with excellent mechanical properties including oxide glass fibers and amorphous alloy fibers.There are continuous and discontinuous oxide glass micro-fibers. Discontinuous oxide glass micro-fibers can be fabricated by techniques in which a thin thread of melt flowing from the bottom of a container is broken into segments. Continuous oxide micro-fibers can be fabricated by techniques in which a filament of supercooled liquid is drawn from melt. However, oxide glass nano-fibers can be fabricated by chemical vapor deposition, laser ablation, sol-gel, and thermal evaporation methods. Fabrication techniques of amorphous alloy fibers are very different from those of oxide glass fibers. These techniques adopt in-rotating-water spinning method, melt-extraction method, Taylor method, nanomoulding method, fast drawing method, melt drawing method, and gas atomization method.Microscale oxide glass fiber has a facture strength as high as 6 GPa. The fracture strength of nanoscale oxide glass fiber can reach 26 GPa which is close to the theoretical strength of 30 GPa. On the other hand, the plasticity of microscale amorphous alloy fibers is mediated by shear banding. The shear band spacing decreases with reducing sample size in bending. However, there is no tensile plasticity in microscale amorphous alloy fibers. When the sample size is smaller than the size of shear band core (500 nm), inhomogeneous plastic deformation transforms into homogeneous plastic deformation. The tensile plasticity of amorphous alloy is significantly improved. The homogeneous plastic deformation is mediated by catalyzed shear transformation. The catalyzed shear transformation may be the origin of hardening behaviors of nanoscale amorphous alloy fibers.Fianlly, we summary the unsolved problems in the fabrications and mechanical behaviors of amorphous fibers, and discuss the prospect of amorphous fibers.
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