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Nitrogen is an important element for the growth of flue-cured tobacco and is closely related to its yield and quality. In order to pursue higher economic benefits, excessive fertilizer is generally applied in flue-cured tobacco production, which is unfavourable for the sustainable development of flue-cured tobacco production and for the environment. In 2016 and 2017, experiments using different nitrogen fertilizer application rates in flue-cure tobacco were conducted in Yunnan province, and the changes in agronomic, economic and chemical indices as well as in residual soil nitrogen were compared. Linear and quadratic models were used to compare the response of tobacco to nitrogen fertilizer. With increasing nitrogen fertilizer rate, the proportions of superior to medium tobacco and the average price of flue-cured tobacco leaves initially increased and then decreased, while fresh weight, dry weight and the proportion of inferior tobacco showed the opposite trend. Total sugar and reducing sugar contents decreased with increasing nitrogen fertilizer rates, while total nitrogen and nicotine contents increased. Sensory evaluation scores had the highest value when 90 kg N/ha and 120 kg N/ha were applied. Soil nitrate contents increased as nitrogen fertilizer rate increased. The quadratic model was suitable for the response of cultivar K326 to nitrogen and 90 kg N/ha could meet the needs of cultivar K326.
We study the breakup of confined fluid threads at low flow rates to understand instability mechanisms. To determine the critical conditions between the earlier quasi-stable necking stage and the later unstable collapse stage, simulations and experiments are designed to operate at an extremely low flow rate. The critical mean radii at the neck centres are identified by the stop-flow method for elementary microfluidic configurations. Two distinct origins of capillary instabilities are revealed for different confinement situations. One is the gradient of capillary pressure induced by the confinements of geometry and external flow, whereas the other is the competition between the capillary pressure and internal pressure determined by the confinements.
In this paper, a diffuse-interface immersed boundary method (IBM) is proposed to treat three different thermal boundary conditions (Dirichlet, Neumann, Robin) in thermal flow problems. The novel IBM is implemented combining with the lattice Boltzmann method (LBM). The present algorithm enforces the three types of thermal boundary conditions at the boundary points. Concretely speaking, the IBM for the Dirichlet boundary condition is implemented using an iterative method, and its main feature is to accurately satisfy the given temperature on the boundary. The Neumann and Robin boundary conditions are implemented in IBM by distributing the jump of the heat flux on the boundary to surrounding Eulerian points, and the jump is obtained by applying the jump interface conditions in the normal and tangential directions. A simple analysis of the computational accuracy of IBM is developed. The analysis indicates that the Taylor-Green vortices problem which was used in many previous studies is not an appropriate accuracy test example. The capacity of the present thermal immersed boundary method is validated using four numerical experiments: (1) Natural convection in a cavity with a circular cylinder in the center; (2) Flows over a heated cylinder; (3) Natural convection in a concentric horizontal cylindrical annulus; (4) Sedimentation of a single isothermal cold particle in a vertical channel. The numerical results show good agreements with the data in the previous literatures.
SG-III laser facility is now the largest laser driver for inertial confinement fusion research in China. The whole laser facility can deliver 180 kJ energy and 60 TW power ultraviolet laser onto target, with power balance better than 10%. We review the laser system and introduce the SG-III laser performance here.
Epilepsy is now recognized as the second most common neurological disease in China. To determine the genetic cause of epileptic encephalopathy, we performed a multiomics study using mouse models of controls, anticonvulsant mice treated with five drugs and epileptic mice. Based on genome-wide profiling analysis, we discovered four genes in the epileptic mouse group with differentially-expressed mRNA. After isobaric tags for relative and absolute quantification (iTRAQ) validation, only one gene, SNCA, remained, which was associated with apoptotic response of neuronal cells, and regulation of dopamine release and transport. We also identified three miRNAs targeting SNCA, out of which mmu-miR-21a-3p demonstrated a seven-fold change in expression between control and epileptic mice.
Microtubule analysis is of significant value for a better understanding of normal and pathological cellular processes. Although immunofluorescence microscopic techniques have proven useful in the study of microtubules, comparative results commonly rely on a descriptive and subjective visual analysis. We developed an objective and quantitative method based on image processing and analysis of fluorescently labeled microtubular patterns in cultured cells. We used a multi-parameter approach by analyzing four quantifiable characteristics to compose our quantitative feature set. Then we interpreted specific changes in the parameters and revealed the contribution of each feature set using principal component analysis. In addition, we verified that different treatment groups could be clearly discriminated using principal components of the multi-parameter model. High predictive accuracy of four commonly used multi-classification methods confirmed our method. These results demonstrated the effectiveness and efficiency of our method in the analysis of microtubules in fluorescence images. Application of the analytical methods presented here provides information concerning the organization and modification of microtubules, and could aid in the further understanding of structural and functional aspects of microtubules under normal and pathological conditions.
The two-dimensional (2D) Ga-nitride/air photonic quasi-crystals (PQC) were successfully fabricated by the technique of focused Ga ion beam (FIB) milling on GaN based epitaxial wafers. The effects of the PQC on the current injected edge emitting GaN-based light emitters were investigated. The quasi-crystal structures studied in this work are based on square-triangular tiling with 8-fold or 12-fold symmetry. The air hole diameter in the different PQC patterns was varied from 95nm up to 1200nm, the filling factor of air hole was in the range of 10% to 50% and the depth of the hole was 90nm to 370nm, respectively. Among these, the nearest center-to-center distance of the holes and/or the lattice constant was reached to be 170nm. The photonic quasi-crystals on the GaN-based light emitters demonstrated a two to three factor of magnitude enhancement of surface extractive emission. The blocking of the propagation of planar-guided modes by the photonic quasi-crystals was observed. By comparison of symmetry effect among the triangular lattice PC and PQCs, it was found that the GaN-based photonic quasi-crystal (PQC) with 12-fold symmetry provided a much favorable enhancement of the extractive light emission over that of triangle lattice PC and 8-fold symmetric PQC as well.
In this paper, we report on the experiment results of wet oxidation of Si1-xGex on SiO2. AES and XPS measurements were performed to study the effect of the oxidation on the Si1-xGex layer. A possible mechanism was proposed.
SiH4 and GeH4 Deposition and In-Situ Doping of SiGe/Si Strained Heterostructures by Rapid Thermal Process Very Low Pressure Chemical Vapor Deposition method have been studied in this paper. Ge incorporation rate increases to a maximum value and then decreases as temperature increases, the growth rate of SiGe alloy reaches its maximum value and then decreases as Ge composition increases. Ge incorporation also enhances Si deposition rate in SiGe alloy. The Boron and Phosphorus doping would change thegrowth rate of SiGe layers and the sharp doping interfaces in SiGe/Si heterostructures have been obtained.
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