学前教育专业毕业生对母校教学培养的反馈——兼与在校生的比较

为考察学校教学培养的效果及了解毕业生对母校的需求,本研究对安徽省各地2994名工作不满4年的学前教育专业毕业生和安徽省8398名来自19所大、中专院校的学前教育专业在校生进行调查,结果显示对于同样类型的课程,毕业生的满意度显著高于在校生,在校生中高年级学生的满意度显著高于中、低年级学生;无论是毕业生还是在校生对学校课程的满意度都是大专院校学生显著高于中职学校学生;对于学校培养对自身专业素养的促进作用,毕业生认可度很高,在校生认可度较低;毕业生认为自身最欠缺教育科研能力和自然科学知识;毕业生希望母校继续提供帮助和指导的愿望非常强烈。学校应重视来自毕业生的反馈,努力建立多校联合的职前职后一体化、多维度的教育服务平台。

Improving uniform scattering device for straw-smashing,back-throwing,no-tillage planter under complete straw mulching condition

With the objective of obtaining a completely straw-mulched field,when no-tillage mechanical sowing is implemented with straw smashing,delivering,and back-throwing approaches,it may be difficult to scatter the smashed straw uniformly during a succeeding wheat sowing step.This is because the previous rice straw is substantial in quantity and has a high humidity and toughness,which may easily result in non-uniform straw mulching and thus sparse and weak seedlings of wheat.Therefore a force-dispersing and uniform-scattering device was designed.With the number of scattering impellers,impeller angle,and impeller rotation speed as the main factors and the percentage of pass for the scattering width and non-uniformity of the straw mulching as the assessment indices,single-factor experiments and orthogonal regressive tests were performed,and a dual-index(percentage of pass for the scattering width and non-uniformity of the straw mulching)fitted regression equation was established.The test results suggested that the main factors(from primary to secondary)that influence the indices were the impeller rotation speed,number of scattering impellers,and impeller angle.The optimal parameter combination for the uniform scattering device was four rows of impellers with an angle of 15°,rotation speed of 1015 r/min,percentage of pass of 72.65%for the scattering width,and a non-uniformity of 13.8%in the straw mulching.This combination can be used to realize a uniform scattering of the smashed straw along the seedling rows on the after-sowing ground.According to the field investigation of the wheat growth,the wheat emergence rate was 90.7%.The research results can provide a reference for improving the uniform scattering device for a straw-smashing,back-throwing,no-tillage planter for obtaining a completely straw-mulched field,enhancing the quality of the machinery operation,and ensuring good and strong seedlings after sowing.

Determination of damaged wheat kernels with hyperspectral imaging analysis

Hyperspectral imaging was applied to classify the damaged wheat kernels and healthy kernels.The spectral information was extracted from damaged wheat kernels and healthy kernels samples.The effective wavelengths were obtained from spectral of 865-1711 nm by X-loadings of principal component analysis(PCA)and successive projection algorithm(SPA)method,respectively.Partial least square method(PLS)and least square-support vector machine(LS-SVM)were then used to build classification models on full spectral data and effective wavelengths dataset,respectively.The results showed that the classification accuracy of every LS-SVM model was the best,being 100%.While the accuracy of the PLS model was slightly lower,still over 97%.The confusion matrix showed that several damaged wheat kernels samples were misclassified as healthy samples,while all healthy samples were correctly classified.The overall results indicated that hyperspectral imaging could be used for discriminating the damaged wheat kernels and could provide a reference for detecting other grain kernels grading degrees.Further,this study can provide a research basis for the development of online or portable detectors on grain damaged kernels recognition,which will be beneficial for grain grading or post-harvest quality processing of other grains.

Adaptabilities of different harvesters to peanut plants after cutting stalks

At present,there are no harvesters specifically adapted to process peanuts after cutting stalks.In particular,methods for harvesting peanuts after cutting stalks have not been reported thus far.Therefore,to utilize peanut stalks as feed when harvesting plastic-film-grown peanuts,and to improve industry benefits,a three-stage harvesting method is proposed herein.In view of the three-stage harvesting method,the peanut stalks are cut before digging,with the remaining peanut plants being shorter,thereby increasing the peanut pod-stalk ratio.To investigate the adaptabilities of existing harvesters in harvesting peanuts after cutting stalks,three types of peanut harvesters-the self-propelled pick-up combine harvester,trailed pick-up combine harvester,and peanut picker were used to conduct a comparative test on harvesting intact peanut plants and plants after cutting stalks.The loss,breakage and impurity rates were used as evaluation indicators.The loss rates of these three harvesters were 14.64%,16.44%and 1.33%;the breakage rates were 21.28%,21.92%and 20.00%,and impurity rates were 4.60%,8.76%and 9.06%.Analysis of variance showed that cutting stalks had a significant impact on the work qualities of the three harvesters(p<0.05).With regard to the loss rate,results revealed that:the two peanut combine harvesters could not be adapted to harvest peanut plants after cutting stalks.The three harvesters had good adaptability to harvest peanut plants after cutting stalks,considering the breakage rate;however,based on the impurity rate,the three harvesters could not be adapted to harvest peanut plants after cutting stalks.The losses of the two combine harvesters consisted mainly of dropped and missed picking,with the sum of the losses accounting for 99.87%and 97.99%of the total losses of the two harvesters,respectively;this suggests that the drum pickup of the combine harvesters could not adapt to harvesting the peanut after cutting stalks.The breakage rates of the three harvesters were considerably reduced,suggesting that the pod picking devices of the three harvesters were suitable for harvesting the peanut after cutting stalks;the impurity rates of the three harvesters were considerably increased,indicating that the pod picking and cleaning devices of the three harvesters were not suitable for harvesting peanut after cutting stalks.To improve the adaptabilities of the harvesters,it is suggested that the speed of pickup elastic tooth,lateral spacing between adjacent elastic teeth,concave screen hole size of pod picking device,the structure and motion parameters of cleaning device should be optimized.The results of this study provide a reference for the development and improvement of peanut harvesters suitable for harvesting peanuts after the cutting of stalks.

Optimization and experiment on key structural parameters of no-tillage planter with straw-smashing and strip-mulching

Accelerate the quality of smashed-straw laying and enhance the effect of seed-bed arranging for no-tillage planter with straw-smashing and strip-mulching in full stubble covered paddy have become imperative in implementing modern conservation tillage.Considering the perfect operating performance(passability and stability)of the developed no-tillageplanter,this study intends to optimize the structure design of smashed-straw diversion device and strip-rotary tillage device.Dynamics equations of smashed straw and kinematics models of rotary blades were established through theoretical analysis,and the principal factors that affecting straw strip-laying quality and seed-bed arranging effect were specified.The influence of out-enlarge angle(η)and slide-push angle(γ)of the diversion device on the coefficient of variation(ζ1)of cover-straw width,and the influence of rotary tillage-blade number(N)and configuration in a singlerotary plane on the broken rate(ζ2)of strip soil were completely analyzed.And then,based on the systematic analysis and integrated scheme,operating performance and field verification tests using the optimized no-tillage planter were thoroughly performed.The results of the performance tests indicated that the out-enlarge angle(η)had a highly significant influence on the coefficient of variation(ζ1),and the slide-push angle(γ)had a significant influence on(ζ1).The rotary tillage-blade number(N)had a highly significant influence on the broken rate(ζ2),and the slide-push angle(γ)had a significant influence on(ζ2).The obtained optimal combination of these key structure parameters through comprehensive analysis wasη=45°,γ=40°,and N=4.Field verification test results indicated that the optimized no-tillage planter achieved mean values of ζ1=10.47%and ζ2=90.95%,which satisfied the relevant operation quality and cultivation agricultural requirement of conservation tillage equipment,and provided technical references for developing the similar no-tillage planter of straw crushing and returning.