教育信息化2.0:技术何以变革教育

随着“互联网＋”教育、教育大数据、人工智能等教育应用理念和技术的迅速普及,开展了近30年的教育信息化工程以党的十九大胜利召开为标志开始进入教育信息化2.0时代。但观之近年来“校校通工程”“农远工程”“三通两平台”“微课教学”等“先进技术”教育应用效果不显著后,教育工作者集体开始反思。本文即从教育信息化2.0的“悖论”谈起,分别从“技术惯性”和“技术耐性”角度反思前进中的教育与教育技术,探索出教育信息化2.0创新发展路径。最后,文章还以教育与技术相互观照的角度展望了教育信息化2.0的美好愿景。

建筑外墙保温施工中施工技术应用

针对建筑外墙保温施工技术进行分析,阐述了外墙保温节能施工技术特点,同时介绍了外墙保温节能技术的优点,并提出了建筑外墙保温施工存在的问题,内容有:外墙内保温技术问题,外墙外保温技术问题,混合技术存在的问题。探讨了建筑外墙保温技术施工技术要点,内容包括:工艺流程,制备施工浆料,建筑外墙特殊位置的施工要点,控制耐性技术等。

Effect of Polyamine Priming on Chilling Tolerance of Lolium perenne during Seed Imbibition

[Objective] This study aimed to investigate the effect of potyamine priming on physiological and biochemical variations of Lolium perenne embryos and seed germination. [Method] With annual Lolium perenne （Diamond T and Grazing-8000） as experimental materials, after priming with 0.5 mmol/L putrescine （Put）, spermidine （Spd） and spermine （Spm） for 24 h and chilling imbibition at 5 ℃ for 12, 24, 36 and 48 h, the effect of Put, Spd and Spm priming on chilling tolerance and germination ability of annual Lolium perenne seeds during imbibition was investigated. [Result] Put, Spd and Spm priming improved the activities of peroxidase （POD）, catalase （CAT）, superoxide dismutase （SOD） and ascorbate peroxidase （APX） and content of soluble protein content under low temperature stress, significantly in-creased the germination rate, and shortened the average germination duration. After chilling imbibition for 48 h, compared with the control, the average germination rate of annual Lolium perenne seeds was improved by 15.5% and 12.0% after Put, Spd and Spm priming, and the average germination duration was shortened by 1.21 and 1.14 d. During seed imbibition, the chilling tolerance of Grazing-8000 was stronger than that of Diamond T. Overall, Put, Spd and Spm treatment could increase the chilling tolerance of annual Lolium perenne seeds during imbibition, and improve the germination ability of seeds under low temperature stress. [Conclusion] Results of this study provided theoretical basis for the application of seed priming technology in the production of annual ryegrass.

Transfer DREB into Lolium perenne L. to improve its drought tolerance

A method of Agrobacterium tumefaciens mediated transformation for perennial ryegrass was developed using the calli of ryegrass derived from mature enrbryos. The calli were inoculated with a disarmed A. tumefaciens strain EHA105 harboring binary vector p2328. Vector p2328 contained transcription factor DREB1B and neomycin phosphotransferase （npt H） genes which were driven by promoters of rd29B and CaMV35S, respectively. The inoculated calli were selected on paromomycin- or kanamycin-containing media till the established plants being transferred to soil. Six tmnsgenic plants with DREB1B had been obtained from perennial ryegrass strain Tove. PCR and Southern-blotting showed that npt Ⅱ and DREBIB genes were integrated in perennial ryegrass genome. Stress treatment confirmed that transgenic plants with higher drought tolerance were obtained.

Current Research Status of Heterodera glycines Resistance and Its Implication on Soybean Breeding

Heterodera glycines （i.e., soybean cyst nematode, SCN） is the most damaging nematode pest affecting soybean crop worldwide. This nematode is managed by means of crop rotation with selected resistant sources. With increasing reports of virulent SCN populations that are able to break the resistance within commonly used sources, there is an increasing need to find new sources of resistance or to broaden the resistance background. This review summarizes recent findings about the genes controlling SCN resis- tance in soybean, and about how these genes interact to confer resistance against SCN in soybean. It also provides an update on molecular mapping and molecular markers that can be used for the mass selection and differentiation of different resistance lines and cultivars in order to expedite conventional breeding programs. In-depth knowledge of SCN parasitism proteins and soybean resistance responses to the pathogen is critical for the diversification of resistant sources through gene modification, gene stacking, or incorporation of novel sources of resistance through backcrossing or genetic engineering.

Method of reliability tolerance design based on EDA technology and its application on DC hybrid contactor

Tolerance design, including tolerance analysis and distribution, is an important part of the electronic system’s reli- ability design. The traditional design needs to construct mathematic model of material circuit, which involves large amount of workload and lacks of practicability. This paper discusses the basic theory of electronic system’s reliability tolerance design and presents a new design method based on EDA (Electronic Design Automatic) software. This method has been validated through the application research on reliability tolerance design of the DC hybrid contactor’s control circuit.

Development Prospect and Strategies of Water-saving and Drought-resistance Rice

Water-saving and drought-resistance upland rice has become a preferable choice for cotton farmlands ready for changing crops or paddy fields with water in short,because simplified and mechanical cultivation can be applied for the rice varieties of drought resistance and high yield.At present,it has been applied with an area of 400 000 hm2 in Hunan Province and the area continues growing.The research bred and introduced the relevant cultivation technology standard applicable to local water-saving and drought-resistance rice varieties in order to improve farmer＇s benefits.

Improvement of surface corrosion resistance for magnesium alloy by combining thermal spray and cast-infiltration

The present work focuses on a new method combining cast-infiltration with thermal spraying technology to improve the surface corrosion resistance of magnesium alloy.A zinc-based alloy layer was fabricated on the surface of AZ91D magnesium alloy. The microstructure of the layer was characterized by scanning electron microscopy equipped with an energy dispersive X-ray spectroscopy(EDS).The phase constituent of these alloys was identified by X-ray diffractometry(XRD).The analysis results reveal that a zinc-based alloy layer with a thickness of 700μm can form on the surface of AZ91 alloy matrix.The layer is composed of Mg7Zn3,MgZn and a small amount of α-Mg solid solution.The results indicate that the corrosion-resistance of the specimen with a zinc-based alloy layer is much better than that of the specimen without the layer after being immersed in 5%NaCl solution for 240 h, and the layer is more protective for the AZ91 alloy.

Effect of crack-closure treatment on fatigue durability of cracked rib-to-deck welded joints in steel bridge decks

To evaluate the effect of treating long cracks with the impact crack-closure retrofit(ICR)technique,three rib-to-deck welded specimens with a crack length of about 100 mm were tested.The metallographic structure,crack section,crack propagation life,and stress variation were analyzed.Finite-element models were also developed,and some optimal values of certain parameters are suggested according to the simulated results.The results show that new crack sources are generated on both sides of the ICR-treated region because of the stress distribution.The fatigue lives of cracked specimens with long cracks are significantly improved by the technique.Considerable residual compressive stress is also induced,and so it is suggested that the optimal impact angle to be applied to real bridges should be 70°.The stress at the weld root is distributed uniformly with the crack closed,and the optimal crack-closure depth is 4 mm.To evaluate the effect of different crack-closure depths in tests,it is recommended that a hot-spot stress method which is extrapolated by three reference points should be adopted.

Drought Tolerant Criterion of Wheat Genotypes Using Carbon Isotopes Discrimination Technique

Drought tolerant analysis using carbon isotopes discrimination could be useful tool to decide a genotype with high adaptation to drought. A pot culture experiment was conducted in glass house at the IAEA （International Atomic Energy Agency） laboratories, Seibersdorf, Austria to analyze drought tolerant of wheat genotype using carbon isotopes discrimination technique. Four wheat genotypes viz., LU-26s, Bhittai, Roshan, Taifu, were tested. There were two treatments： Control （normal irrigation） and Drought （@ 30% field capacity of the control treatment）. Drought treatment was imposed after two weeks of germination. The experiment was continued up to 10 weeks after germination and was terminated at flowering stage. The data were recorded in terms of plant height, number of tillers, shoot dry weight and carbon isotopic ratio （δ）. Results showed that genotype LU-26s was found to have best performance under drought condition, with minimum decrease in the growth parameters i.e., plant height, number of tillers and shoot dry weight. High CID （carbon isotopes discrimination） values were also observed in genotype LU-26s, showing close positive correlation between SDW （shoot dry weight） and CID. It is therefore concluded that carbon isotopes discrimination can be an important criterion for the selection of wheat genotypes for drought prone areas.

Optimization of tribological parameters over WC-12%Co laser alloyedpearlitic ductile iron using Taguchi based Grey relational analysis

Pearlitic ductile irons(PDIs)are used in transportation and nuclear energy industries.In heavy loading situation,the service life of PDI is affected by numerous tribo aspects.In this study,surface of the PDI is alloyed with WC-12%Co powder using a high power fibre laser.The wear properties of the base material and laser alloying samples were investigated by tribometer with various parameters,i.e.,temperature,load and sliding speed.Based on experimental test,the load has maximum percentage of contribution and followed by sliding speed and working temperature.The optimized tribological parameters by Grey relational analysis(GRA)were established and those values are closely matched with predicted values.Besides,base material and laser alloying surfaces were examined through Vickers hardness machine,scanning electron microscopy(SEM)and roughness tester.The laser altered specimen shows no defects and improves the wear properties than substrates.The identified optimal tribological parameters are load of 30 N,speed of 0.5 m/s and working temperature of 300℃,and load of 30 N,speed of 0.5 m/s and working temperature of 200℃ for base metal and laser alloying samples,respectively.

Coating of microbially produced calcium carbonate onto stone materials

The coatings of microorganism-induced calcium carbonate onto the stone surface carried out by using both of the immersion method and coating method were investigated. Various analysis and testing techniques such as scanning electron micrograph （SEM） and X-ray diffraction （XRD） were used to characterize the deposited mineral layer. The adhesive property, acid re- sistance, frost resistance, light and aging resistance, water adsorption and permeability were investigated in detail. The results showed that both immersion method and coating method could produce calcium carbonate granules with sizes ranging from 1 to 10 pm and form a layer of dense mineralization membrane which is about 50 to 100 pm thick. Immersion method was more efficient than coating method. The large cohesive force between calcium carbonate layer and stone materials could improve the acid rain resistance as well as excellent heat tolerance, frost resistance and light aging resistance. The coating process could not only help the stone materials maintain its original permeability with the aid of calcium carbonate layers but also improve the penetration resistance significantly. Therefore, this type of technology shows a great potential in the protection of stone relics.

Principles and Practice of Forestation in Saline Soil in China

With world population growth arable land area is decreasing. Saline soil is an important naturalresource. However it has not been well reclaimed owing to adverse conditions. Forestation is one way of saltysoil utilization; on the other hand, it can improve soil quality as well. The mechanism of salinity tolerance isthe basis for tree species selection when planting in salt affected soil. Different plants have various way ofsalinity tolerance, some are salt-exclusion, e.g. Elaeagnus angustifolia; some are salt-secretion, e.g. Tamarixspp.; some are salt-dilution, e.g. Hordeum vulgare; some are salt-avoidance, e.g. Rhizophora apiculata. Treesare favorable, which are salt tolerant and drought or waterlogging tolerant, as well as grow fast. After treespecies have been decided, site preparation including change or exchange of soil is necessary. Meanwhilesuitable density of trees and planting time must be carefully considered in terms of soil conditions andclimatic characteristics. Now a large scale of forests has been established in salt-affected soil in China by themeans discussed in the paper, and protect forest system along coast plays important roles in socio-economicsustainable development and improvement of eco-environment.

Study on Cultural Technologies and Salt-resistance of Nitraria sibirica in Coastal Areas with Serious Salt-affected Soil

In this research, five Nitraria sibirica provenances such as Dayilu were selected to do experiment of salt-resistance, combining fixed plots test with typical plot investigation, measuring survival rate and growth as main indicators. The experiments of main cultural technology were done on Nitraria sibirica in 4 types of site preparation, 3 types of planting, 3 designs for planting density. The Nitraria sibirica experiments for the effects of curbing salt and improving soil were done by testing soil nutrients, salt content, soil physical properties as focal points in typical site of 3-4 years woods. The experiment results showed that the Nitraria sibirica could survive well with soil salt content of 0.6%, and that survival rate declined distinctively as soil salt content exceeded 0.8%. However, high soil salt content did not influence growth in the year of planting. There were obvious differences in salt-tolerance among Nitraria sibirica provenances; Dayilu was the best on salt-tolerance, the other 4 provenances had no differences, and obviously inferior to Dayilu. The different types of site preparation clearly influenced planting survival rate, conserving rate and growth. The method of two-ploughing-two-harrowing was the best among all 4 types of site preparation. Seed forestation was largely limited, bared-rooted seedling forestation may be popularised when soil salt content was less than 1% and soil moisture content was better in spring. Forestation with container seedling was suited to coastal saline soil in rainy season. The optimum planting density of Nitraria sibirica was 2 505/ha in the Yellow River Delta area in view of coverage rate, yield of fruits and cost of planting. Generally speaking,Nitraria sibirica could effectively refrain soil from accumulation of salt in the surface soil, decrease salt content and increase soil nutrient, and heighten soil capillary pore rate.