基于“力行”教育的课堂教学模式改革——以明溪县第二实验小学为例

文章提出以“三学一引”为主要内容的“力行”教育课堂教学改革,即学生“自学”“互学”“研学”和教师“引导”相结合。通过“三学一引”,提升课堂教学的有效性,促进学生核心素养的培养。

“力行”教育思想引领下的德育教育

目前,“力行”教育观念要求学校关注学生的全面发展,德育教育也不例外。我国教育不断发展,教师在教学时应注重对学生的德育教育。小学阶段作为为学生未来学习奠定基础的时期,“力行”教育思想引领下的德育教育可以促进学生的人格发展。教师在小学阶段对学生进行思想道德教育,能够规范其行为,促使其成长为德才兼备的综合型人才。把“立德”作为“树人”前提的同时,教师还应倡导知行合一,引导学生树立正确的人生观、世界观和价值观,让每名学生都能养成良好的行为习惯,学做结合、德智相融、知行合一,从而使其全面、健康、快乐地成长。

“力行”陪伴教师成长——江苏省江阴市徐霞客实验小学教师“力行团队”的特色实践

江苏省江阴市徐霞客实验小学将“力行”教育作为学校特色发展的生长点,实施富有特色的教师“力行团队”建设,通过“力行教师”愿景的描绘、多元学习方式的营造、教育科研的深度实践,努力打造有“动力”、有“魅力”、有“能力”、有“毅力”的“力行团队”,切实提升了“力行团队”教师的专业素养。

仁者“力行”:教学悖论与教师自由实践

教学悖论指教师教育教学过程中存在的必须解决却永难得到答案的一系列困惑与矛盾,如语言暴力与无言之教的悖论、规训与自我创造的悖论、理想之境的描绘与苦难之境的揭示之间的悖论、功利追求与精神修养的悖论等等。教学悖论对教师的自由实践造成了重大影响。教师自由实践的本质和精髓在"力行",教师权力的真正体现也在"力行"。教师的自由实践是一种精神实践,也是一种科学的政治实践。教师自由实践的最高境界表现为教师能进行原创性教学,即教师创造课堂、教师创造学生。而这一切自由实践的根本则在教师能够自我创造。

Effect of interrupted aging on mechanical properties and corrosion resistance of 7A75 aluminum alloy

The effects of interrupted aging on mechanical properties and corrosion resistance of 7A75 aluminum alloy extruded bar were investigated through various analyses,including electrical conductivity,mechanical properties,local corrosion properties,and slow strain rate tensile stress corrosion tests.Microstructure characterization techniques such as metallographic microscopy,scanning electron microscopy(SEM),and transmission electron microscopy(TEM)were also employed.The results indicate that the tensile strength of the alloy produced by T6I6 aging is similar to that produced by T6I4 aging,and it even exceeds 700 MPa.Furthermore,the yield strength increases by 52.7 MPa,reaching 654.8 MPa after T6I6 aging treatment.The maximum depths of intergranular corrosion(IGC)and exfoliation corrosion(EXCO)decrease from 116.3 and 468.5μm to 89.5 and 324.3μm,respectively.The stress corrosion factor also decreases from 2.1%to 1.6%.These findings suggest that the alloy treated with T6I6 aging exhibits both high strength and excellent stress corrosion cracking resistance.Similarly,when the alloy is treated with T6I4,T6I6 and T6I7 aging,the sizes of grain boundary precipitates(GBPs)are found to be 5.2,18.4,and 32.8 nm,respectively.The sizes of matrix precipitates are 4.8,5.7 and 15.7 nm,respectively.The atomic fractions of Zn in GBPs are 9.92 at.%,8.23 at.%and 6.87 at.%,respectively,while the atomic fractions of Mg are 12.66 at.%,8.43 at.%and 7.00 at.%,respectively.Additionally,the atomic fractions of Cu are 1.83 at.%,2.47 at.%and 3.41 at.%,respectively.

Prediction of Hot Deformation Behavior of 7Mo Super Austenitic Stainless Steel Based on Back Propagation Neural Network

The hot compression tests of 7Mo super austenitic stainless(SASS)were conducted to obtain flow curves at the temperature of 1000-1200℃and strain rate of 0.001 s^(-1)to 1 s^(-1).To predict the non-linear hot deformation behaviors of the steel,back propagation-artificial neural network(BP-ANN)with 16×8×8 hidden layer neurons was proposed.The predictability of the ANN model is evaluated according to the distribution of mean absolute error(MAE)and relative error.The relative error of 85%data for the BP-ANN model is among±5%while only 42.5%data predicted by the Arrhenius constitutive equation is in this range.Especially,at high strain rate and low temperature,the MAE of the ANN model is 2.49%,which has decreases for 18.78%,compared with conventional Arrhenius constitutive equation.

论教学悖论与教师自由实践

教学悖论指教师教育教学过程中存在的必须解决却永难得到答案的一系列困惑与矛盾,如语言暴力与无言之教的悖论、规训与自我创造的悖论、理想之境的描绘与苦难之境的揭示之间的悖论、功利追求与精神修养的悖论等等。教学悖论对教师的自由实践造成了重大影响。教师自由实践的本质和精髓在＂力行＂,教师权力的真正体现也在＂力行＂。教师的自由实践是一种精神实践,也是一种科学的政治实践。教师自由实践的最高境界表现为教师能进行原创性教学,即教师创造课堂、教师创造学生。而这一切自由实践的根本则在教师能够自我创造。

Effect of traveling magnetic field on gas porosity during solidification

The effects of traveling magnetic field on degassing of aluminum alloys were investigated, and the critical radius of the pores was calculated. The results show that the critical radius of the pores decreases with increasing the magnetic density linearly when the traveling magnetic field is applied during solidification, and the use of traveling magnetic field promotes the heterogeneous nucleation of pores. After the gas dissolved in the metal liquid accumulates to form large bubbles, the traveling magnetic field forces the bubbles to the surface of molten metal, so the gas is easy to separate from the melt in the liquid stage. The number of pores in the sample decreases with increasing the intensity of traveling magnetic field.

Segregation in fusion weld of 2219 aluminum alloy and its influence on mechanical properties of weld

Three kinds of welds were made using low frequency pulse current variable polarity tungsten inter gas （LPVPTIG） with argon shielding, direct current TIG （DCTIG） with helium shielding and high frequency pulse current variable polarity TIG （HPVPTIG） with argon shielding, respectively. It was found that macrosegregation bands with large amount of thick continuous eutectics and microporosities formed in the LPVPTIG weld due to the fluctuation of the pulse varied heat input. Only microsegregation existed in the DCTIG weld and HPVPTIG weld. However,the HPVPTIG weld had lower extent of Cu microsegregation since its welding speed was slower. The tensile results indicated that the mechanical properties of the weld decreased with the increase of the segregation extent of Cu and porosities, and LPVPTIG weld had lower tensile properties in the longitudinal direction than those in the transverse direction due to the macrosegregation bands.

Casting effect on compressive brittleness of bulk metallic glass

An interesting phenomenon of cooling-rate induced brittleness in Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass （BMG） was reported. It was found that the as-cast BMG specimens exhibited a brittle-ductile transition when the larger specimens were machined into smaller specimens through removing the cast-softening surface layer by layer. After compression tests, the as-machined small specimens, owing to the absence of the cast-softening surface, displayed highly dense and intersecting shear bands, and extensive plastic deformation. This is in contrast to the catastrophic failure and low deformability in the as-cast large specimens. More free volume was detected in the smaller as-fractured specimens, by differential scanning calorimetry, which may be attributed to the occurrence of strain softening and increased plasticity. Compared with the relatively smooth fracture surface in the smaller specimens, the larger specimens showed more diverse features on the fracture surface due to their graded structures.

Mechanical behavior of Al-Zn-Mg-Cu alloy under tension in semi-solid state

In order to study the hot fractures in relation to the semi-solid processing, the tensile tests of an extruded 7075 aluminum alloy which is based on Al?Zn?Mg?Cu system were carried out in the high temperature solid and semi-solid states at different strain rates. The results show that the tensile behavior can be divided into three regimes with increasing the liquid fraction. The alloy first behaves in a ductile character, and as the temperature increases, the fracture mechanism changes from ductile to brittle which is determined by both of liquid and solid, and lastly the fracture mechanism is brittle which is totally dominated by liquid. At strain rates of 1×10?4, 1×10?3 and 1×10?2 s?1, the brittle temperature ranges are 515?526, 519?550 and 540?580 °C, respectively. Two equations which are critical for tensile behavior are proposed.

Effect of heat treatment on microstructure and mechanical property of Ti-steel explosive-rolling clad plate

The effect of heat treatment on microstructure and mechanical properties of the Ti-steel explosive-rolling clad plate was elaborated by optical microscopy （OM）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, transmission electron microscopy （TEM）, micro-hardness test and shear test. The composites were subjected to heat treatment at temperature of 650-950 ~C for 60 min. The results show that the heat treatment process results in a great enhancement of diffusion and microstructural transformation. The shear strength decreases as the treatment temperature increases. Heated at 850 ℃ or below, their shear strength decreases slowly as a result of the formation of TiC in the diffusion interaction layer; while at the temperature of 850 ℃ or above, the shear strength decreases obviously, which is the consequence of a large amount of Ti-Fe intermetaUics （Fe2Ti/FeTi） along with some TiC distributing continuously at diffusion reaction layer.

Static and dynamic mechanical behaviour of ECO-RPC

Ecological reactive powder concrete (ECO-RPC) with small sized and differentvolume fraction steel fibers was prepared by substitution of ultra-fine industrial waste powder for50% to 60% cement by weight and replacement of ground fine quartz sand with natural fine aggregate.The effect of steel fiber volume fraction and curing ages on the static mechanical behaviour ofECO-RPC was studied. Using the split Hopkinson pressure bar technique, the dynamic mechanicalbehaviour of ECO-RPC was investigated under different strain rates. The results show that the staticmechanical behaviour of ECO-RPC increases with the increase of steel fiber volume fraction andcuring ages. The type of ECO-RPC with the substitution of 25% ultra-fine slag, 25% ultra-fine flyash and 10% silica fume is better than the others with compressive strength, flexural strength, andfracture energy more than 200 MPa, 60 MPa and 30 kJ/m^2, respectively. ECO-RPC has excellent strainrate stiffening effects under dynamic load. Its peak stress, peak strain and the area understrain-stress curve increase with the increase of strain rate. Its fracture pattern changes frombrittleness to toughness under high strain rates.

Towards the Integrating Wind Power into Power Grid in China

With abundant wind resources and high pressure imposed on en-vironmental protection, wind power development has a promising future. Butdue to intermittent nature, wind power can bring into full play only if being con-nected into power grid to ensure its supply reliability and continuity, aswell as operational economy. However, technical and market barriers haveprevented wind power from integrating into power grid. To foster wind powerdevelopment, these barriers should be removed by both government incentivepolicies and sophisticated technologies.

Hot deformation behavior and processing maps of Mg-Zn-Cu-Zr magnesium alloy

The deformation behaviors of a new quaternary Mg-6Zn-1.5Cu-0.5Zr alloy at temperatures of 523-673 K and strain rates of 0.001-1 s-1 were studied by compressive tests using a Gleeble 3800 thermal-simulator.The results show that the flow stress increases as the deformation temperature decreases or as the strain rate increases.A strain-dependent constitutive equation and a feed-forward back-propagation artificial neural network were used to predict flow stress,which showed good agreement with experimental data.The processing map suggests that the domains of 643-673 K and 0.001-0.01 s-1 are corresponded to optimum conditions for hot working of the T4-treated Mg-6Zn-1.5Cu-0.5Zr alloy.

Study on the Recycling Agricultural System Operation Mechanism Focusing on Pig Farming

According to the characteristics of circular agricultural mode focusing on pig farming and by dint of system dynamics mode-based analysis techniques to analyze the characteristics,the operation force for the recycling agricultural system focusing on pig farming was put forward.

Method for calculating the capacity of bus bay

The bus operating characteristics are analyzed at the bus bay using the trajectories depending on the current status of buses. On this basis, a method for calculating the capacity of the bus bay is developed, which considers the queue probability, the dwell time distribution and the waiting time for a gap in the traffic stream at the curb lane. Then, the distribution model of the dwell time is developed using the survey data of Hangzhou city. And the log-normal distribution shows the best fitting performance. The capacities of the bus bay are computed with the Matlab program under different distribution parameters of the dwell time and different traffic volumes at the curb lane. The results show a large range of traffic capacity as the distribution parameters and traffic volumes change. Finally, the proposed model is validated by measurement and simulation, and the average relative errors between the calculated values and the measured and simulated values are 8.78% and 5.28%, respectively.

Capacity model of on-rampmerging section of urban expressway

To establish the empirical capacity model of an on- ramp merging section, the Erlang distribution is first selected to define the time headway distribution, and then the gap acceptance theory is applied to develop the basic capacity model of the on-ramp merging section. Since not all the time headways on the shoulder lane can be made full use of by on- ramp vehicles, a modified capacity model is developed, which takes the usage probability of time headway into consideration. Then, a model of capacity discount coefficient ~： is developed. Finally, based on the modified capacity model and the model of capacity discount coefficient, an empirical merge capacity model which contains the shoulder lane volume, critical gap, and the distance from nose to merging point, is constructed. Results show that, compared with other models, the proposed model is more reasonable since it takes merging section geometry into consideration, and it is easy to apply. The merge capacity varies with the shoulder lane volume, the critical gap, the distance between the nose and the merging point, and the design velocity of the shoulder lane and ramp.