4,279 research outputs found
Research and Optimization on the Incentive Mechanism for High School Teachers under the Background of the New College Entrance Examination—Taking Huizhou L High School as an Example
After the reform of the new college entrance examination, new changes such as the class-taking system have posed new challenges to teachers’ work. Based on the two-factor theory of American management scientist Herzberg, taking L High School in Huizhou City as an example, this paper uses the questionnaire method and interview method to investigate the front-line high school teachers, and investigates the front-line teachers’ opinions on the existing incentive mechanism and evaluate. Combined with questionnaire data and interview content, the deficiencies of the existing incentive mechanism are analyzed. Through the survey, L secondary schools scored poorly in motivation, and there were unsatisfactory items in hygiene factors. The main reasons are that the performance appraisal mechanism is not scientific enough, the school decision-making not unfair and open enough, and the training and learning do not meet the needs. After sorting out the existing deficiencies and reasons, this paper puts forward improvement measures for hygiene factors and motivation factors, including improving the performance appraisal system, reforming professional title evaluation and other measures to ensure the effect of teachers’ job satisfaction and mobilizing teachers’ work enthusiasm and to provide references for other schools to promote the sound development of my country’s education
Opportunistic Random Media Access in WLANs
This thesis proposes a new medium access protocol for IEEE 802.11 wireless local area networks, which is called opp01tunistic medium access. The protocol changes the media access opportunities of nodes by adjusting the contention window dynamically according to the different bit rates. Thereby, the protocol can reduce collision and improve throughput significantly. The n·aditional IEEE 802.11 standards access channel with binary exponential back-off algorithm and all nodes choose the back-off interval from the same initial range. The new protocol in this thesis divides nodes as well as contention windows in proportion to data rate. It offers three methods to group nodes and contention window with different lower boundary or upper boundary. So, nodes can choose their back-off intervals distinguished based on their channel conditions. As a consequence, the nodes with better channel condition will get smaller back-off values, that enables these nodes win the contention with a larger probability. Besides, the protocol takes a data rate normalized average history throughput into the computation of contention window to achieve temporal fairness. The protocol has been implemented based on ath9k wireless driver and the experimental results show that the new protocol gets 20% more throughput compare to the 01iginal IEEE 802.11 n protocol. Besides, in order to verify the perfo1mance in a large network, some simulations conducted in NS-3 which shows proposed protocol have good performance as well
E/M dips. Evidence for lipids regularly distributed into hexagonal super-lattices in pyrene-PC/DMPC binary mixtures at specific concentrations
We have examined the effect of 1-palmitoyl-2-(10-pyrenyl)decanoyl-sn-glycerol-3-phosphatidylcholine (Pyr-PC) concentration on the ratio of excimer fluorescence to monomer fluorescence (E/M) in L-alpha-dimyristoylphosphatidylcholine (DMPC) multilamellar vesicles at 30 degrees C, with special attention focussed on the smoothness of the curve. We observed a series of dips, in addition to kinks, in the plot of E/M versus the mole fraction of Pyr-PC (XPyrPC). The observation of dips is a new finding, perhaps unique for Pyr-PC in DMPC since only kinks were observed for Pyr-PC in L-alpha-dipalmitoylphosphatidylcholine (DPPC) and in egg yolk phosphatidylcholine (egg-PC) (Somerharju et al., 1985. Biochemistry. 24: 2773–2781). The dips/kinks observed here are distributed according to a well defined pattern reflecting a lateral order in the membrane, and distributed symmetrically with respect to 50 mol% Pyr-PC. Some of the dips appear at specific concentrations (YPyrPC) according to the hexagonal super-lattice model proposed by Virtanen et al. (1988. J. Mol. Electr. 4: 233–236). However, the observations of dips at XPyrPC > 66.7 mol% and the kink at 33.3 mol% cannot be interpreted by the model of Virtanen et al. (1988). These surprising results can be understood by virtue of an extended hexagonal super-lattice model, in which we have proposed that if the pyrene-containing acyl chains are regularly distributed as a hexagonal super-lattice in the DMPC matrix at a specific concentration YPyrPC, then the acyl chains of DMPC can form a regularly distributed hexagonal super-lattice in the membrane at a critical concentration (1-YPyrPC).(ABSTRACT TRUNCATED AT 250 WORDS
Application of lower bound limit analysis with second-order cone programming for plane strain and axisymmetric geomechanics problems
Ph.DDOCTOR OF PHILOSOPH
Synergistic effects of dual-electrocatalyst FeOOH/NiOOH thin films as effective surface photogenerated hole extractors on a novel hierarchical heterojunction photoanode structure for solar-driven photoelectrochemical water splitting
Herein, we report the rational design of a novel hierarchical V2O5/BiVO4 heterojunction photoanode structure with rGO interlayer that functionalises as photogenerated electron collector, and dual electrocatalyst thin films of FeOOH and NiOOH as photogenerated hole extractors for solar-driven PEC water splitting. Results showed that the novel hierarchical FTO/V2O5/rGO/BiVO4/FeOOH/NiOOH photoanode exhibited an unprecedented and stable photocurrent density of 3.06 mA/cm2 at 1.5 V vs Ag/AgCl, and an apparent cathodic onset potential shift down to 0.2 V under AM 1.5 G simulated solar light illumination. The significant enhancement in PEC performance is ascribed to band potentials matching between V2O5 and BiVO4 in forming a Type II staggered heterojunction alignment, and further coupling with rGO interlayer and dual-electrocatalyst thin films as photogenerated electron collector and photogenerated hole extractors, respectively. Three different configurations of the novel hierarchical FTO/V2O5/rGO/BiVO4 photoanodes without electrocatalyst, with mono- and dual-electrocatalyst thin films were systematically examined. It was proven though EIS and IMPS measurements that the dual-electrocatalyst configuration photoanode exhibited the shortest transit time (τ) of 31.8 ms for the diffusion of photogenerated electrons to the counter electrode, and the lowest charge transfer resistance across the interface of electrode/electrolyte as estimated using the Randles-Ershel model. We believe that the proof-of-principle work described here not only provides an in-depth understanding on the roles of electrocatalyst thin films but also provides a design guide over the incorporation of electrocatalyst materials for further improving the photogenerated charge carrier dynamics in photoanodes used in solar-driven PEC water splitting
An Analysis of the Trend of China’s Export Trade to the USA Based on R Language
After President Trump came to power, in order to change the “imbalance” between China and US trade, he launched a trade war with China, which led to increase uncertainty in China-US trade and increased export volatility. Based on R language environment, this paper compares the advantages and disadvantages of seasonal ARIMA (p, d, q) model and double-index ETS (A, N, A) model in short-term forecast of China’s total export value to the United States. Then, the double-index ETS (A, N, A) model is selected to predict the trend of China’s export trade to the United States in the months of 2009-2020. The forecast results show that China’s export to the United States has seasonal characteristics. The export fluctuation is smaller than that in 2018, but the total value of exports has decreased significantly. Finally, some suggestions are put forward
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