Papers by Keyword: Growth

Abstract: Using fractal theory simulation of dendrite crystal DLA growth model of pure substance, the undercooling during solidification process of crystal nucleation is simulated; and then in the crystal nuclei are formed on the basis of a pure substance, the phase field model and combined with the finite difference method further differentiation simulation of dendrite crystal growth. According to MATLAB programming, the simulation results obtained by field and temperature field can be seen in the DLA growth, growth model with random premise, for the same kind of material simulated dendrite crystal have both similarities and differences exist. Then, we can get the conclusion, through fractal growth of DLA model with phase field model of dendrite nucleation, growth process is carried out the simulation results, a simple by phase field model is more accord with the dendrite crystal in the experiment.

Abstract: The response of Iris pseudacorus to the introduction of earthworms and to a variety of substrates in constructed wetland systems was investigated under greenhouse conditions. The growth of I. pseudacorus was influenced by the presence of earthworms and the type of substrate. Plants grown on a sand substrate had the fewest seedlings and the smallest plant size. Because the sand substrate started with the lowest nutritional value, the addition of earthworms resulted in the largest increase in fresh and dry weights of I. pseudacorus, when compared with the other pairs of substrate treatments, with or without earthworms. The addition of earthworms increased pod production in I. pseudacorus, especially on substrates of mixed sand and soil, and with mixed sand and organic matter. Pod production in I. pseudacorus pots with earthworms varied by substrate.

Abstract: The response of growth characteristics (tillering number, plant height, stem diameter, leaf length, and leaf width), and nitrogen (N) and phosphorus (P) concentration of three wetland plants to the introduction of earthworms in a constructed wetland (CW) was investigated under greenhouse conditions. The growth characteristics, and N and P concentration of wetland plants were influenced by earthworms. The addition of earthworms enhanced three wetland plants growth, especially benefiting to the flower formation of the C. indica. The addition of earthworms to CW, the increased rate of plant height, stem diameter, leaf length, and leaf width could be summarized as follows: C. indica > P. australis > T.augustifolia. N and P concentration of Stems, leaves and flowers of wetland plants was increased by addition of earthworms into constructed wetland, and N and P concentration distributed in wetland plants followed the order of flowers> leaves > stems. The N and P removal rate could be enhanced by addition of earthworms into constructed wetland.

Abstract: We report graphene thickness, uniformity and surface morphology dependence on the growth temperature and local variations in the off-cut of Si-face 4H-SiC on-axis substrates. The transformation of the buffer layer through hydrogen intercalation and the subsequent influence on the charge carrier mobility are also studied. A hot-wall CVD reactor was used for in-situ etching, graphene growth in vacuum and the hydrogen intercalation process. The number of graphene layers is found to be dependent on the growth temperature while the surface morphology also depends on the local off-cut in the substrate and results in a non-homogeneous surface. Additionally, the influence of dislocations on surface morphology and graphene thickness uniformity is also presented.

Abstract: In an effort to grow single crystal SiC fibers for seed crystals the following two growth methods have been coupled in this work: traveling solvent and laser heated floating zone to create the solvent-laser heated floating zone (Solvent-LHFZ) crystal growth method. This paper discusses the results of these initial experiments, which includes, source material, laser heating, and analysis of the first ever SiC crystals (confirmed by synchrotron white beam x-ray topography)

Abstract: A pot-grown experiment was conducted to investigate the effect of limited irrigation on growth, storage water amount of every organ and water use of Jatropha curcas L.seedlings. Four watering treatments were designed in the study, i.e. (W1: 0.3θ_f，W2: 0.5θf，W3: 0.7θf，W4: 0.9θf，θf is the field capacity). Results show that Jatropha curcas L.seedlings has the higher resistance ability to drought-stress, it can survival in lower soil moisture (0.3θ_f) , and has certain growth potential. Dry mass of every organ in plant shows that shoot＞branch and master rod＞leaf＞root＞petiole. Storage water capability of unit dry mass for every organ in plant shows that petiole＞branch and master rod or shoot＞leaf＞root. Compared to W4 treatments, W2 reduced irrigation water by 27.1%, mean leaf area of Jatropha curcas L.seedlings for W2 reduced by 25.8%, but root-shoot ratio increased by 6.1%, meanwhile, mean storage water capability of unit root, lateral branch and master rod, leaf, shoot and total plant dry mass of Jatropha curcas L.seedlings for W2 increased by 15.4%，1.3%，7.4%，0.6% and 1.8%, respectively. But mean root, shoot and total plant dry mass accumulation of Jatropha curcas L.seedlings for W2 only reduced by 11.4%、17.7%、15.8%, respectively, therefore, irrigation water use efficiency and total water use efficiency of Jatropha curcas L.seedlings for W2 increased by 15.5%，14.9%, respectively. It is clear that W2 treatment not only increased water use efficiency, but increased regulation storage water capability, thus W2 treatment’s Jatropha curcas L.seedlings improved water regulation and controlled water balance capability and resistance ability to drought-stress.

Abstract: The study was conducted to investigate the effects of commercial composite enzymes (CE) on growth, carcass composition and specific enzyme activities of juvenile flounder Paralichthys lethostigma. Four diets were formulated: one diet contained no CE (the control), the three others provided graded levels of CE (0.5%, 1% and 1.5%). Each diet was fed to pentaplicate of flounder juveniles for 28 days in aquaria (50×40×30 cm, water volume 50 L). The growth parameters (final wet weight, specific growth rate: SGR, feed conversion rate: FCR and apparent digestibility: AD) were significantly affected (P0.05). The CE had significant effects (P<0.05) on the specific activities of neural protease, alkine protease and amylase, but not on acid protease, amimopeptidase and alkine phosphatase. The pattern of the specific activities of neural protease, alkine protease and amylase was similar to that of SGR with fish fed diets containing 1.5% of CE exhibited the significantly higher activities (P<0.05). The results demonstrated that the supplement of CE in diets could significantly improve growth performance and digestive enzyme activities of flounder juveniles.

Abstract: The problem of phase competition during reactive diffusion is revisited. Nucleation of an intermediate phase at an interface under external fluxes in the neighboring phases is considered in the frame of kinetic Fokker-Planck approach. Effective nucleation barrier depending on the divergence of external fluxes is introduced. New suppression/growth criteria are obtained.

Abstract: Transmission electron microscopy (TEM) characterizations were carried out on a set of UO₂ thin foils previously implanted at room temperature with 400 keV Xe²⁺ and 250 keV Kr²⁺ ions at the fluence 7.10¹⁵ at.cm^-2 (equivalent to 1 at.%/at. UO₂). The experiment was devoted to the study of the evolution of the fission gases bubbles populations with increasing temperature. Annealings were performed in the laboratory furnace at 600°C, 800°C, 1000°C for 12h, 1400°C for 4h and 1500°C for 2h under Ar-5%H₂ atmosphere. For each annealing condition and for as-implanted specimens the bubble population has been characterized in size and number density. A comparison between Xe and Kr has been done that showed a similar behaviour. Globally, from the as-implanted sample to the 1500°C annealed, the bubbles growth phenomenon and the microstructure evolution with temperature was put in relieve.

Abstract: The control of the plastic anisotropy during forming of a metallic sheet requires detailed knowledge on its microstructure and, especially, crystallographic texture. During the thermo-mechanical processing of aluminium sheet products in commercial production lines the material experiences a complex history of temperature, time and strain paths, which result in alternating cycles of deformation and recrystallization with the associated changes in texture and microstructure. Thus, computer-based alloy and process development requires integration of models for simulating the evolution of microstructure, microchemistry and crystallographic texture into process models of the thermo-mechanical production of Al sheet. The present study focuses on recent developments in linking softening modules that simulate the progress of recovery and recrystallization with the following texture changes to deformation and microchemistry models.