Papers by Keyword: Growth

Abstract: CdS nanocrystals were synthesized by a solvent-thermal method in ethylenediamine at different temperature and time. The samples were investigated by XRD, TEM, Uv-vis absorption and PL spectroscopy. The solvent-thermal temperature at 200 °C is an optimal reaction temperature for preparing CdS nanorods with high crystallinity. The PL spectra exhibited two typical emissions: near band edge emission (centered at ~520nm) and defect emission (a broad peak in the range of 550-750nm). The defect emission decreased gradually and disappeared finally with the reaction time increasing from 1 to 12h, but the near band edge emission increased. This revealed that the quality of the CdS samples improved by degrees as the reaction time increased. The growth of single-crystalline CdS nanorods followed three steps; (a) CdS nuclei formed by reacting Cadmium chloride dihydrate and thiourea in ethylenediamine at 200 °C, (b) CdS nuclei grew into thin nanowhiskers after 1h reaction, (c) the growth of CdS nanorods based on nanowhiskers via a Ostwald ripening process.

Abstract: The Ni-coated TiH₂ composite powder was prepared by electroless plating and the concentration of reducing agent, reaction temperature, reaction time, PH value and so on were optimized by orthogonal experiment design. The Ni/TiH₂ composite powder morphology and composition was analyzed by scanning electron microscopy (SEM), Energy Dispersive spectroscopy (EDS), X-ray diffraction (XRD); the plated Ni layer growth mechanism was explored preliminary. The Optimization technical parameters: the plating temperature was 85, the pH value was 10 and the hydrazine concentration was 100ml/L. Complete coating and uniform thickness of the Ni layer with average coating thickness about 2.0μm was successfully prepared with the optimization technical parameters. The growth mechanism of the coating followed the Ostwald ripening mechanism. Compared the TiH₂ uncoated with Ni layers particles, the TiH₂ composite powder could efficiently delay the starting time of gas release by approximately 80s.

Abstract: Zinc sulfide (ZnS) quantum thin films have been deposited from precursors with a variety of OH- concentration onto microscope glass substrates by chemical bath deposition method. The growth and structural properties have been investigated. XRD patterns of ZnS films obtained from acidic solution showed a favorable wurtzite structure, while for those obtained from alkaline solution, showed a sphalerite structure. The growth studied of the deposited films has also shown that the OH- played a vital role in nucleation and the film growth.

Abstract: Phase transitions can be usually observed in nature and technology which effectively utilize certain types of these transitions. An approach to modeling phase transition processes on the basis of the mathematical theory of growing solids is developed. Liquid-solid and gas-solid phase transitions are under consideration. Main attention is paid to the processes of solid phase growth and deformation.

Abstract: The use of bacteria for red tides control is a promising method, but the microalgae sterile is the basis of the research. The effects of Amipicillin, Gentamycin sulfate, Nomycin sulfate, Chcoramphencol, Kanamycin sulfate on the growth, Chl-a and MDA content of Prorocentrum minimum were studied under laboratory conditions. The results showed that Gentamycin sulfate and Kanamycin sulfate could stimulated the growth of P. minimum under lower concentrations (0.05mg/mL), and the growth stimulation was significant (pP. minimum under higher concentrations. The growth inhibition was significant (pP. minimum showed the significant difference in sensitivity to five kinds of antibiotics. The inhibition of Chcoramphencol was the largest, while Kanamycin sulfate was the smallest in the five kinds of antibiotics. The Chl-a content was decreased (p<0.05) by five kinds of antibiotics when the concentration was 2.00mg/mL. Besides, the accumulation of MDA content was observed by Chcoramphencol treatment. Therefore, Chcoramphencol could not be used for the microalgae sterile.

Abstract: Growth, photosynthesis and the nitrate reductase activity of Ulva pertusa were determined at fluctuating salinity treatments. Compared with the control, SGR of Ulva pertusa were higher at fluctuating salinity treatments. The photosynthetic rates were higher at the fluctuating salinity treatments of 30-25 and 30-20, and lower at the fluctuating salinity treatments of 30-15. Ulva pertusa got higher nitrate reductase activity at fluctuating salinity treatments of 30-20 and 30-15. It demonstrated that Ulva pertusa was able to change the photosynthetic rates and the nitrate reductase activities to adapt to salinity fluctuations.

Abstract: Water stress is an important approach to use water resources efficiently and remit the agricultural water shortage. Hemarthria compressa is one of perennial grasses, a pasture of high quality, which has abundant species resources in China. To explore the response of the growth, yield and water use efficiency(WUE) of Hemarthria compressa under water stress, this study, adapting pot experiment, imposed three water stress degree (LD, MD and SD) treatments and a control treatment on Hemarthria compressa. The data of growth indicators during control period, yield and total water consumption were obtained. The results show a noticeable inhibitory action of water stress on the growth of Hemarthria compressa. Along with the intensifying of water stress, plant height increment, leaf area, total biomass, dry matter of each organ and yield decreased, and the root-shoot ratio increased firstly and inclined to slump finally. Plants under the middle water stress treatment achieved the greatest WUE of 38.25 kg/m³. The first 10d in the water control period was the most sensitive period of the pasture responding to water stress.

Abstract: In order to investigate the ability of Pteris vittata restoring Zn polluted soil, water cultured experiment is utilized to study the enriching ability of Pteris vittata to Zn, and the detoxification mechanism of Pteris vittata to Zn. The experimental results show that Pteris vittata has certain enriching ability to Zn,and the translation coefficient of Zn in Pteris vittata reaches 1.0. With the increasing of Zn application amount, chlorophyll and soluble sugar contents of Pteris vittata show ascending first and then descending,O2-• and MDA contents continuously ascend,starch content continuously descends.These results show that soluble sugar, starch,O2-• and MDA have detoxification effect,and can enhance the resistance of plant to heavy metal.

Abstract: In the last years oxide materials for electronics show significant progress. However, many details regarding technology control of the properties have to be solved. For electronics, thin films and heterestructures are important taking advantage of integration and synergetic concepts leading to new types of devices and functionalities. It is notable that, while fabrication of new devices and materials showing new phenomena are booming, the growth principles and concepts are somehow developing slowly within this general trend. This is because in many cases, growth of materials is very personalized. Understanding of the bi-directional relationship between the general and particular principles deserves attention. The immediate benefit is that knowledge on growth for one material can be transferred to another one. In our work we have analyzed such relationships for some oxide multicomponent perovskites. Materials used in our examples are Bi-Sr-Ca-Cu-O and YBa₂Cu₃O₇, (Ca, Sr)CuO₂, (Ca, Ba)CuO₂ and Bi₄Ti₃O₁₂. Presented thin films or heterostructures are with c-axis and non-c-axis orientations and based on these examples we discuss some of the growth principles.

Abstract: Immobilization of microencapsulated cell is a kind of membrane technology. Therefore, the characteristics of membrane have a great impact on the growth of microorganisms. This study is designed to achieve the greatest growth rate of microencapsulated cell, Escherichia coli were immobilized in AC microcapsules made with different type of chitosan and then cultured in the Luria-Bertani medium. Effect of deacetylated degree (DD), molecular weight, membrane formation time and the pH of chitosan on the swelling ratio, cell release and proliferation were investigated at 2, 4, 6, 12, 24and 48h respectively. The results showed that the DD has no obviously influence on terminal biomass concentration, but the swelling ratio of membrane reached lowest when the DD was 90%. The biomass concentration increased with the rising of chitosan Mw and membrane formation time. Especially, the terminal biomass concentration near to 6.5×106·mL in the microcapsules made with 10KDa chitosan Mw ands 15min membrane formation time. Moreover, the swelling ratio closed to lowest point as the chitosan solution pH was 6.3.