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1.
杨文举 《中国教育研究与创新》2006,3(1):16-17
有着学业水平差异的学生称作“异质学生”,异质学生的数学教学首先要使学生尽可能大地形成共性基础,应该让学生能得到最优化的发展。在新课标的指导下,数学教师在实施人文教育的同时,要针对异质学生的不同特点,在班级授课中形成独特的教材,这一教材应该是课本的同构体或异构体。教师要倡导自主学习,要发展地评价学生。 相似文献
2.
BackgroundPlanctomycetes is a phylum of biofilm-forming bacteria with numerous biosynthetic gene clusters, offering a promising source of new bioactive secondary metabolites. However, the current generation of chemically defined media achieves only low biomass yields, hindering research on these species. We therefore developed a chemically defined medium for the model organism Planctopirus limnophila to increase biomass production.ResultsWe found that P. limnophila grows best with a 10 mM sodium phosphate buffer. The replacement of complex nitrogen sources with defined amino acid solutions did not inhibit growth. Screening for vitamin requirements revealed that only cyanocobalamin (B12) is needed for growth. We used response surface methodology to optimize the medium, resulting in concentrations of 10 g/L glucose, 34 mL/L Hutner’s basal salts, 23.18 mM KNO3, 2.318 mM NH4Cl and 0.02 mg/L cyanocobalamin. The analysis of amino acid consumption allowed us to develop a customized amino acid solution lacking six of the amino acids present in Aminoplasmal 10%. Fed-batch cultivation in a bioreactor using the optimized medium achieved a final ΔOD600 of 46.8 ± 0.5 after 108 h, corresponding to a cell dry weight of 13.6 ± 0.7 g/L.ConclusionsThe optimized chemically defined medium allowed us to produce larger amounts of biomass more quickly than reported in earlier studies. Further research should focus on triggering P. limnophila biofilm formation to activate the gene clusters responsible for secondary metabolism.How to cite: Kruppa OC, Gerlach D, Fan R, et al. Development of a chemically defined medium for Planctopirus limnophila to increase biomass production. Electron J Biotechnol 2021;54. https://doi.org/10.1016/j.ejbt.2021.09.002. 相似文献
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Recognizing inconsistencies between the extant fear appeal theories and emotion literature, this research integrated cognitive appraisal theory and functional emotion theory into a fear appeal literature and proposed a model that describes a process through which both fear and anxiety can contribute to adaptive responses. Findings from an experiment (N = 927) supported the predictions. Fear and anxiety emerged as distinct constructs. Perceived susceptibility was a stronger predictor of anxiety than fear, while perceived severity was a stronger predictor of fear than anxiety. In addition, greater fear and anxiety led to greater response efficacy through increased motivation to obtain protection-related information and heightened attention to such information, thus mediating the threat and coping appraisal processes. The SEM model testing the predictions showed that perceived susceptibility had the strongest total effects on protection intention, followed by anxiety, perceived severity, and fear. 相似文献
4.
PU Jun-ping ZHENG Jian-jun 《浙江大学学报(A卷英文版)》2006,7(11):1831-1838
INTRODUCTION The differential quadrature method (DQM) was proposed by Bellman and Casti as an analogous ex- tension of the quadrature method for integrals (Bellman and Casti, 1971; Bellman et al., 1972). It can be essentially expressed as the values of the de- rivatives at each grid point as weighted linear sums approximately of the function values at all grid points within the domain under consideration. As a distinct numerical solution technique to obtain the initial and/or boundary … 相似文献
5.
通过试验手段对受冲击后的变压器内部线圈绕组受损情况进行检测,对于正确引导变压器的检修,有效地减少设备停电时间具有极其重要的现实意义。同时,对于变压器的检测提供可行的变压器测试方法,以及判断变压器是否适合重新投入运行、投入后是否存在事故隐患。 相似文献
6.
Effective extraction of elastase from Bacillus sp. fermentation broth using aqueous two-phase system 总被引:1,自引:0,他引:1
INTRODUCTION Aqueous two-phase system (ATPS) is widely used in biochemistry and biotechnology for purifica- tion of proteins (Diamond and Hsu, 1992; Balasubramaniam et al., 2003), enzymes (Pan et al., 2001; Bim and Franco, 2000), amino acids (Li et al., 2002), antibiotics (Yang et al., 1994; Guan et al., 1994), nucleic acids (Ohlsson et al., 1978; Kimura, 2000), aroma compounds (Marco et al., 2000) and lactic acid (Planas et al., 1998). ATPS is mainly composed of two-incompatible p… 相似文献
7.
利用H(o)lder不等式得到了微分形式的局部 Ar (λ1,λ2 ;Ω)-加权Poincaré型不等式,所得结果能被广泛应用于某些重要方程解的高阶可积性理论. 相似文献
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9.
Response surface methodology (RSM) was used to optimize the fermentation medium for enhancing pyruvic acid production by Torulopsis glabrata TP19. In the first step of optimization, with Plackett-Burman design, ammonium sulfate, glucose and nicotinic acid were found to be the important factors affecting pyruvic acid production significantly. In the second step, a 23 full factorial central composite design and RSM were applied to determine the optimal concentration of each significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the critical components were obtained as follows: ammonium sulfate 0.7498 (10.75 g/L), glucose 0.9383 (109.38 g/L) and nicotinic acid 0.3633 (7.86 mg/L) with a predicted value of maximum pyruvic acid production of 42.2 g/L. Under the optimal conditions, the practical pyruvic acid production was 42.4 g/L. The determination coefficient (R^2) was 0.9483, which ensures adequate credibility of the model. By scaling up fermentation from flask to jar fermentor, we obtained promising results. 相似文献
10.
电机运行时会产生各种电磁和共模干扰,影响电机参数的准确获取。传统的电机参数检测方法不能充分滤除现场出现的各种干扰信号,从而增大测量误差,影响测量参数的准确性。为此,本文设计了一种实用的干扰抑制技术,大大提高了测量参数的准确性和精确性。最后通过GSM/GPRS无线网络数字传输技术,将下位机采集到的电机参数发送给上位机中心专家诊断端系统,进行在线实时故障诊断和排除。 相似文献