Papers by Keyword: Growth

Abstract: The study on the effects of three unary and binary micro-catchment mulching methods including film mulching ridge and ditch plantation, film-mulching ridge and ditch film-mulching plantation and film-mulching ridge and ditch film-mulching straw plantation on growth of corn and different precipitation years was conducted in allusion to the low and unstable yield of corn in the western Liaoning province of China and in comparison with the traditional plantation model. Under the condition of this experiment, through film-mulching ridge and ditch film-mulching plantation and film-mulching ridge and ditch plantation, the time for seedling emergence of corn was shortened and the emergence rate of corn was increased. Through film-mulching ridge and ditch film-mulching straw plantation, the time for seedling emergence of corn was prolonged and the emergence rate of corn was increased in median water or dry years, but the emergence rate of corn was reduced in the high flow year. By contrast to traditional plantation model, film-mulching ridge and ditch film-mulching plantation and film-mulching ridge and ditch plantation boosted the increase in plant height and leaf area of corn and promoted dry matter accumulation in the early period of growth while the growth was slow, the plant height, leaf area and dry matter accumulation was always at he minimum value through film-mulching ridge and ditch straw mulching plantation in the early period of growth, but the growth rate was expedited in the late period during growth. Through film-mulching ridge and ditch straw mulching plantation, due to many reasons such as the growth process ahead of schedule and high temperature, the signs of precocity or premature senility come into being and leaf area and chlorophyll content decreases swiftly; through film-mulching ridge and ditch straw mulching plantation, the descent velocity of leaf area and chlorophyll content were reduced and the leaf senescence was postponed. In different precipitation years, the increases in water use efficiency of micro-catchment plantation were different, smaller in high flow year while larger in dry or median water year.

Abstract: Microalgae are microscopic heterotrophicautotrophic photosynthesizing organisms with enormous potential as a source of biofuel. In the masses of biomasses, microalgae has the advantages of high lipid, large biomass, short growth cycle and easy cultivation and with microalgae as the raw material. Light condition is crucial to cultivation of microalgae.In this paper, the microalgae strain of Chlorella sp. was supplied in BG11 medium, and Cultivation optimization were experimented. The results were showed that growth of chlorella was associated with a saturated light intensity, light intensity which was suitable for the growth of chlorella was 2000Lux. Growth of chlorella required an appropriate light-dark alternation to facilitate matching of photoreaction of photosynthetic process with dark reaction of photosynthetic, appropriate light-dark photoperiod of illumination time which was suitable for the growth of chlorella was 12:12.

Abstract: TiO₂ nanorod arrays grown on FTO (fluorine-doped tin oxide) substrate were prepared in aqueuous solution of hydrochloric acid (HCl) and tetrabutyl titanate (C₁₆H₃₆O₄Ti) using hydrothermal method. TiO₂ nanorod arrays with different morphologies were obtained by systematically changing preparation conditions, including reaction temperature, reaction time, solution pH value, and concentrations of the reactants in the solution. Both morphology and crystalline structure of the samples were characterized. The prepared TiO₂ nanorod arrays were used to assemble dye-sensitized solar cells, whose performances were also presented.

Abstract: Zn-doped CdS dendritic nanostructures were prepared by a simple hydrothermal method. The product displays single-crystalline characteristic. The dendritic crystal is formed by growing along several equivalent directions ([2-1-10],[-1-120]and[-12-10]). Due to doping Zn, the CdS dendritic nanostructures present some beneficial properties and are promising candidates for future applications in optoelectronic nanodevices.

Abstract: In recent years, the use of liquid biofuels in the transport sector has shown rapid global growth, driven mostly by policies focused on achievement of energy security, and mitigation of GHG emissions. Microalgae, as biomass, are a potential source of renewable energy, and they can be converted into energy such as biofuel oil and gas.In this paper, the microalgae strain of Chlorella sp. was supplied in BG11 medium, and Cultivation optimization were experimented. The results were showed that temperature was an important factor which could influence growth and accumulation of secondary metabolite in the cell from accumulation process of biological products, temperature which was suitable for the growth of chlorella was 25°C.

Abstract: Zinc selenide (ZnSe) quantum dot thin films have been deposited onto microscope glass through chemical bath deposition both from original amonia free alkaline precursors and modified precursors with the adding of sodium citrate as complexing agents. The growth and optical properties of samples from original and modified precursors have been investigated. Its shown that the samples obtained with sodium citrate precursors are uniform and with stable index of refraction. And with the adding of sodium citrate, there is an increase in transmittance.

Abstract: To research influence of low light on macrophyte growth, seedlings of Vallisneria natans were transplanted into the waters with 5%, 1%, 0.5% and 0.1% full sunlights, respectively. The results show that germination rates are significantly inhibited with the experiment. In first 20 days leaf formation of new plants aren’t inhibited, and their leaf elongation are promoted. Since then, them of old plants and new plants are remarkably inhibited with the experiment. Though maximum photochemical quantum yield (Fv/Fm), relative electron transport rate (ETR) and non-photochemical quenching (NPQ) of old plants reduce significantly on low light conditions, but V. natans still hsa a certain degree of photoasynthetic capacity on the 80th day. Fresh weight ratio of roots and stems increase with decreasing light intensity. However, it exhibits an opposite trend for leaves. Thus, V. natans has a strong ability of low-light (≤1% full sunlight) tolerance.

Abstract: The study was conducted to investigate the effects of nano-sized titanium dioxide (nTiO2 )on the growth and biophysical characteristics of Chlorella sp.. Chlorella sp. was cultured in HB-4 medium and exposed to 7 levels(0,1,5,10, 20, 40 and 80mg/L)of nTiO2.The results showed that EC50 of nTiO2 was 26.52 mg/L after 96-hr exposure. In 5 levels (0,10, 20, 30 and 40mg/L)of nTiO2 after 96-hr exposure, the content of Chl-a and the soluble protein was reduced with the increasing concentrations. Because of nTiO2 caused the increase of permeability of Chlorella sp.'s membrane, some soluble materials got out of Chlorella sp.'s cell, such as polysaccharide.The value of conductivity and polysaccharide content was increased with concentrations. When the concentrations of nTiO2 were higher than 20mg/L, the physiological function of Chlorella sp. was inhibited obviously, and the activity of peroxidase and dehydrogenase decreased. As a result, there was the potential harm to the aquatic environment by using nTiO2.So the toxicity of nTiO2 and the mechanism of aquatic lives deserved special concern.

Abstract: Growth techniques of high quality AlN and GaN bulk crystals on SiC seeds by sublimation sandwich method are presented. GaN crystals were grown in the temperature range of 1100-1250 °C and with addition of ammonia (NH₃) to prevent GaN decomposition. GaN powder or metallic Ga was used as the source. AlN crystals up to 2 inch diameter have been grown on SiC seeds in the temperature range of 1950 -2050 ⁰С. Kinetic mechanisms and transport features in the sandwich cell are discussed. The achieved high crystal quality has allowed producing semiconductor devices on their basis, in particular, ultraviolet LEDs

Abstract: AlN bulk crystals were grown by the sublimation “sandwich method” on the SiC substrates. Two types of containers were used: (i) Ta container with a surface layer of TaC created by the special annealing in contact with carbon, (ii) TaC container created by pressing of TaC powder. Cryptocrystalline AlN wafers grown by oversublimation of the original industrial high purity AlN powder were used as a vapor source. So a considerable decrease of oxygen concentration in the source (10 – 30 times) was achieved. 4H and 6H SiC bulk crystals grown by Nitride Crystals, Ltd., which were used as wafers, were crack-free, micropipe-free and have a low dislocation density (1- 4^.10³cm^-2). The method allowed to grow thick AlN bulk crystals up to 5mm height and up to two inches in diameter with smooth mirror-like surface. X-ray diffractometry and topography of the grown AlN layers show that FWHMs of the rocking curves in ω-scan lie in the range of 60-120 arcsec.