混合研修对中小学教师教学能力影响因素研究--基于PAST视域的探析

混合式研修活动已成为新时代提升教师专业素养和核心能力的重要途径。基于PAST理论,从教学法设计、研修空间、研修评价和技术支持四维度,探讨中小学教师在混合研修活动中信息化教学能力提升的影响因素,并构建结构方程模型,采用最大似然法、多群组分析等方法对数据进行分析与验证。研究发现,PAST四维度是影响教师参与混合研修的关键因素,其中教学法设计(0.411)与研修空间(0.234)影响较大;性别和任教年资在教师参与混合研修中发挥着重要的调节作用。基于此,研究提出构建“点一面一体”相结合的研修空间结构、创新设计AI支持下的混合研修模式、建立“线上+线下”混合研修协同管理机制等建议,以期为促进教师专业发展提供借鉴。

Contribution to the Study of Fungal Strains Contaminating Peanut Pastes in Bangui (Central African Republic)

Introduction: Peanut pastes are food products resulting from artisanal or industrial processing, used in cooking in Africa in general and in Central African Republic in particular. These peanut pastes are often contaminated by molds and filamentous fungi involved in the degradation of hygienic and organoleptic or even toxicological quality. This study aims to determine the epidemiological profile of molds contaminating peanut pastes sold on the Central African market. Methodology: This was a cross-sectional study carried out from June to September 2023. Samples of peanut pastes sold on Central African market were taken and analyzed at the National Laboratory of Clinical Biology and Public Health using the conventional microbiology method according to ISO 7954 standards. The data obtained were collected in the ODK 2023.3.1 application and analyzed with the Epi Info 7 software. A multivariate analysis by logistic regression, Ficher’s exact test, and chi2 at the 5% threshold (p Penicillium sp.;11.25% of Mucor sp.;10.63% of Aspergillus terrei;3.13% of Aspergillus niger;1.25% of Aspergillus medullans;28.13% of Aspergillus flavus;2.50% of Aspergillus fumigatus. Peanut pastes stored beyond three days were more contaminated (94.19%). Conclusion: The results of this study made it possible to highlight strains of mold that impact the hygienic and organoleptic quality of peanut pastes sold at the Central African market. Most of the isolated strains were the Aspergillus flavus species which is recognized by its toxigenic effects. This species is much more incriminated in the contamination of foodstuffs with the production of the toxin which causes underlying pulmonary pathologies in humans.

图像抠图与copy-paste结合的数据增强方法

提出一种基于图像抠图与copy-paste结合的数据增强方法(matting-paste),采用图像抠图法获取单个垃圾实例的准确轮廓,并对单个实例进行旋转和亮度变换.根据物体轮廓信息,把实例粘贴到背景图上,无需额外的人工标注即可生成新的带有标注的数据,从而提高数据集的多样性和复杂性.结果表明:数据集扩充后的mask比数据集扩充前的识别精度提高了0.039,matting-paste能在已有数据集上有效地扩充数据,进一步提高模型的识别精度.

PAST软件在《生物统计学》教学中的应用

生物统计学是高等院校生命科学相关专业的核心基础课程,是一门集理论性、应用性和实践性于一体的课程。根据生物统计学课程教学中存在的问题,在理论和实践教学中引入PAST软件,以期提升教学效果。本文结合3个具体生物统计学案例,展示了PAST软件的使用过程和计算结果,同时分析了PAST软件的优缺点,为该软件在生物统计学课程教学中的应用提供了参考。

Effect of particle gradation characteristics on yield stress of cemented paste backfill

Along with slurry concentration and particle density,particle size distribution(PSD)of tailings also exerts a significant influence on the yield stress of cemented paste,a non-Newtonian fluid.In this work,a paste stability coefficient(PSC)was proposed to characterize paste gradation and better reveal its connection to yield stress.This coefficient was proved beneficial to the construction of a unified rheological model,applicable to different materials in different mines,so as to promote the application of rheology in the pipeline transportation of paste.From the results,yield stress showed an exponential growth with increasing PSC,which reflected the proportion of solid particle concentration to the packing density of granular media in a unit volume of slurry,and could represent the properties of both slurry and granular media.It was found that slurry of low PSC contained extensive pores,generally around 20μm,encouraging free flow of water,constituting a relatively low yield stress.In contrast,slurry of high PSC had a compact and quite stable honeycomb structure,with pore sizes generally<5μm,causing the paste to overcome a higher yield stress to flow.

基于PAST盲信号分离方法的仿真结果分析

盲信号分离问题在信号处理领域中是一个值得深入研究的很重要的方向。因此关于这个问题已经提出了很多分离算法,能够在一定程度上解决越来越复杂的实际问题。投影逼近子空间跟踪(PAST)是一种很重要的盲信号分离方法。本文就PAST方法用于盲信号分离给出仿真结果并进行性能分析。本文的目的是验证非线性PCA方法用于盲信号分离的有效性,并分析参数取值对分离结果的影响。衡量分离效果的指标是串音误差,程序运行的结果给出了串音误差随算法参数改变的曲线图。

一种基于PAST盲分离的终极无线电信号检测方法

介绍终极无线电的基本架构和盲源分离的基本思想,提出一种基于投影逼近子空间跟踪(PAST)算法的终极无线电信号检测方法.仿真结果表明:该方法是一种可有效用于终极无线电系统中的信号检测方法,它不仅能够检测到系统中用户信号,而且能够在接收端恢复出用户信号.

基于PAST模型的课例研修对教师自我效能感的影响

为解决当前课例研修活动中教学法、评价、空间和技术的支持作用不突出这一问题,文章设计并实施了基于PAST(教学法—评价—空间—技术)模型的课例研修活动,并以我国西部某少数民族自治县课例研修为例,探究基于PAST模型的课例研修对教师自我效能感的影响。研究结果表明:(1)基于PAST模型的课例研修提高了教师自我效能感水平,且教师在课例研修前后的自我效能感存在显著差异;(2)不同性别、学历、教龄的教师在课例研修前后的自我效能感均分别存在显著差异,且研修后的自我效能感水平均高于研修前的自我效能感水平;(3)不同性别、学历、教龄之间的教师自我效能感均不存在显著差异。

An analytical solution for evaluating the safety of an exposed face in a paste backfill stope incorporating the arching phenomenon

In current underground mining, the stability of the exposed backfill face is a basic issue associated with mining design and has been the subject of considerable research in mining safety and efficiency. In this study, an improved analytical solution for evaluating the safety of vertically exposed faces in backfilling was proposed. Based on a differential slice method, the proposed solution emphasizes the arching effect as having the advantages of more rigor and wider scalability. Feasibility of the proposed solution was validated with classic centrifuge results. Good agreement between compared results indicated that the proposed solution skillfully predicts the behavior of the paste centrifuge model. Additionally, calculation of exposed face safety in sequential filling was presented. The proposed solution has practical significance in mine backfill design.

基于MCC-PAST算法的直扩信号PN码序列盲估计

针对在脉冲噪声环境下的直接序列扩频信号的伪随机(PN)码盲估计问题,提出了一种利用最大熵准则投影逼近子空间(MCC-PAST)算法和滑窗技术相结合的PN码盲估计方法。该方法利用最大熵准则,实现了在脉冲噪声背景下对扩频信号的特征进行稳定快速追踪。通过对迭代过程中的特征子空间进行梯度估计,实现了可变遗忘因子(VFF)的自适应更新,使得权值的收敛精度和收敛速度得到同时优化。算法数据存储量小,复杂度低,易于硬件实现和实时数据处理。仿真结果表明,在脉冲噪声环境下该方法对PN序列估计的正确率和稳定性优于传统方法。

Effect of Gluten on Pasting Properties of Wheat Starch

The effect of gluten on pasting properties of wheat starch was studied to provide a scientific basis for the application of gluten in food production and quality improvement in wheat breeding. The pasting properties of blends were analyzed using PH 1391 wheat starch mixed with five different additions of three kinds of gluten （strong-, medium-, and weak-gluten） and the structures of network were observed with microscope. The significant downtrends of peak viscosity, trough viscosity, final viscosity, area of viscosity, setback, and peak time were observed with the increase in the addition of gluten. In general, the average value of them decreased respectively by 3.6, 4.8, 3.4, 3.8, 4.0, and 1.18% of those corresponding indexes of pure starch for every 2% increase in gluten. The decreasing rate of the indexes mentioned above exceeded more than 2% except peak time, but there were no significant influence of gluten addition on breakdown, pasting temperature and pasting time. The inter layer composed of gluten was not observed when the addition of gluten was 10%, as the compound formed of gluten inlaid in the paste of starch, but obvious inter layer was detected when the addition of gluten was 18%. There was significant or remarkable difference among the effects of three different kinds of gluten on the peak viscosity, trough viscosity, area of viscosity, setback, and peak time, but it had no significant difference among the effects of different glutens on pasting temperature and pasting time. The descending order of the effect of different glutens on peak viscosity, trough viscosity, and area of viscosity was strong-, medium-, and weak-gluten, but the order of them for setback was opposite. Both addition and types of gluten significantly affected peak viscosity, trough viscosity, area of viscosity, setback, and peak time, but there were no significant effects of it on peak time and peak temperature.

Strength evolution and deformation behaviour of cemented paste backfill at early ages： Effect of curing stress, filling strategy and drainage

In this study, a pressure cell apparatus is developed to investigate the early age evolution of the strength and deformation behaviour of cemented paste backfill(CPB) when subjected to various loading conditions under different curing scenarios. The different curing scenarios that are simulated include:(1)drained and undrained conditions,(2) different filling rates,(3) different filling sequences, and(4) different curing stresses. The findings show that drainage, curing stress, curing time and filling rate influence the mechanical and deformation behaviours of CPB materials. The coupled effects of consolidation, drainage and suction contribute to the strength development of drained CPB subjected to curing stress. On the other hand, particle rearrangement caused by the applied pressure and suction development due to self-desiccation plays a significant role in the strength gain of undrained CPB cured under stress.Furthermore, curing stress induces slightly faster rate of cement hydration, which can contribute to strength acquisition.

基于PAST处理的机载双基雷达自适应角度-多普勒补偿算法

自适应角度-多普勒补偿算法根据样本数据本身来自适应地估计补偿参数,从而避免惯导系统误差造成的补偿性能下降问题,但该算法必须对杂波协方差矩阵进行估计和特征分解,运算量巨大。针对这一问题,该文研究了基于近似投影子空间跟踪(PAST)处理的自适应角度-多普勒补偿算法,该方法先采用循环迭代处理快速估计出各距离单元主特征向量谱中心的位置参数,避免了矩阵特征分解带来的运算负担,然后通过补偿使得各单元的谱中心重合。仿真结果表明,该方法能有效解决机载双基雷达杂波非均匀问题,其性能与基于特征分解算法相当,但运算量显著降低,便于工程实现。

Effect of Coal Gangue with Different Kaolin Contents on Compressive Strength and Pore Size of Blended Cement Paste

The effects of activated coal gangue on compressive strength, porosity and pore size distribution of hardened cement pastes were investigated. Activated coal gangue with two different kaolin contents, one higher and one lower, were used to partially replace Portland cement at 0%, 10%, and 30% by weight. The water to binder ratio（w/b） of 0.5 was used for all the blended cement paste mixes. Experimental results indicate that the blended cement of activated coal gangue mortar with higher kaolin mineral content has a higher compressive strength than that with lower kaolin mineral content. The porosity and pore size of blended cement mortar were significantly affected by the replacement of activated coal gangue.

支持教师区域研修的PAST模型构建及应用研究

区域研修是区域(县、区)自行组织开展的教师发展模式。调研发现,研修活动设计随意性较强、缺乏有效的理论模型支撑是当前我国区域研修面临的最大问题之一。在文献研究和大规模调研的基础上,以建构主义学习理论、协作学习理论、活动理论和交互理论为指导,构建支持教师区域研修的教学法-评价-空间-技术(PAST)模型,解读核心要素的内涵,厘清核心要素的关系,重点明确核心要素在区域研修活动设计中的含义和作用,介绍模型特征和应用重点、难点,并设计了精准教研支持下的工作坊主题研修活动,为区域研修活动的开展提供有力的理论支撑。

Effects of Papain Hydrolysis on the Pasting Properties of Wheat Flour

As one of the most effective enzymatic modification methods of protein, papain hydrolysis is applied widely in food production, accompanying starch pasting frequently in order to improve industrial quality. Effects of the papain hydrolysis on flour pasting properties were investigated in five papain/flour concentrations and five time-treatments. The structure of starch and protein networks in slurry was investigated under microscope before and after pasting. Results showed that papain hydrolysis influenced the pasting properties of wheat flour significantly through affecting structural characteristics, amylase activity and exotbermic transition, especially during the early stage of hydrolysis. Peak viscosity, trough, final, integral area, and setback significantly decreased along with the increasing concentration of papain. Both hydrolysis time and concentration of papain had obviously effect on the breakdown. Pasting temperature and pasting time increased significantly with the enhancement of papain concentration. Hydrolysis time exerted minor effect on the pasting temperature and pasting time. The average peak time was slightly prolonged by lower concentration of papain, otherwise slightly shortened by higher concentration.

Accurate Measurement of Pasting Temperature by the Rapid Visco-Analyser:a Case Study Using Rice Flour

Pasting properties are among the most important characteristics of starch, determining its applications in food processing and other industries. Pasting temperature derived from the Rapid Visco-analyser （RVA） （Newport Scientific）, in most cases, is overestimated by the Thermocline for Windows software program. Here, two methods facilitating accurate measurement of pasting temperature by RVA were described. One is to change parameter setting to ＇screen＇ the true point where the pasting viscosity begins to increase, the other is to manually record the time （T1） when the pasting viscosity begins to increase and calculate the pasting temperature with the formula of （45/3.8）×（T1-1）＋50 for rice flour. The latter method gave a manually determined pasting temperature which was significantly correlated with the gelatinization temperature measured by differential scanning calorimetry.

Trace Determination of Scandium Using Adsorption Voltammetry of Mix-Polynuclear Complex of Scandium-Calcium-Alizarin Red S at Carbon Paste Electrode

A novel method was described for the determination of ultra trace amount of scandium based on the cathodic adsorptive voltammetry of the mix-polynuclear complex of scandium-calcium-alizarin red S at a carbon paste electrode (CPE). The 2nd-order derivative linear scan voltammograms of the adsorbed complex were recorded by model JP-303 polarographic analyzer from 0.0 to -1.0 V (vs. SCE). The experimental conditions of the working procedure were optimized. The results show that the complex can be adsorbed on the surface of the CPE, yielding one peak at -0.61 V, corresponding to the reduction of the alizarin red S in the mix-polynuclear complex at the electrode. The detection limit of Sc^(3+) is 1.0×10^(-10) mol·L^(-1) for 3 min of accumulation time. The procedure was successfully applied to the determination of trace amount of scandium in the sample ores.

Effect of Pre-wetting Lightweight Aggregates on the Mechanical Performances and Microstructure of Cement Pastes

The water absorption and desorption processes of different types of lightweight aggregates were studied.Subsequently,the influences of pre-wetting lightweight aggregates on compressive strength,microhardness,phase composition,hydration parameters and micromorphology of the cement pastes were investigated.The results showed that the water absorption and desorption capacities of the lightweight aggregates increased with the decrease of the densification degree.With the addition of pre-wetting lightweight aggregates,the compressive strength of the cement pastes would increase.Moreover,the enhancement effect was more obviously with the desorption capacity of pre-wetting lightweight aggregates increasing.Especially,sample S1 with pre-wetting red-mud ceramisites had the highest compressive strength,of which increased to 49.4 MPa after 28 d curing age.The reason is that mainly because the addition of pre-wetting lightweight aggregates can promote the generation of C–S–H gels in the interfacial zone,and the hydration degree of the interfacial zone increases with the water desorption of pre-wetting lightweight aggregates increasing.It is contributed to optimize the microstructure to enhance microhardness of the interfacial zone,resulting in the compressive strength of the cement-based materials improving.Therefore,the pre-wetting lightweight aggregates with high porosity and strength are the potential internal curing agents for high-strength lightweight concretes.

Spatial Distribution of the Increased Porosity of Cement Paste due to Calcium Leaching

Using the tomography image, a method to characterize the 3D spatial distributions of increased porosity was proposed, and the increased porosity distributions of cement pastes with different leaching degrees were given using the current method. The leaching processes of CH/C-S-H and the contribution of CH/C-S-H leaching to porosity evolution were discussed. The proposed method can be applied to all cement- based materials with any leaching degrees. From the quantitative increased porosity results, we find that the CH leaching finished quickly on the sharp CH leaching front.