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941.
高师公共课“教育学”改革对策研究 总被引:4,自引:0,他引:4
高师公共课“教育学”教学现状不尽如人意,有课程自身、学校、教师和学生等多方面的原因。要提高公共课“教育学”的教学质量,必须在课程目标定位、课程资源开发、教学方法与手段、教学研究等多方面进行改革。 相似文献
942.
Centrifugal contactors have many advantages and are favored for reprocessing of spent nuclear fuel and partitioning of high-level waste. A new ?20 mm annular centrifugal contactor for laboratory scale has been developed for the hot test of the total TRPO process. A modular design, a multi-stage group housing design and ceramic bearings are adopted in the new centrifugal contactor. A sampling system and a rotor speed acquisition and monitoring system for ?20 mm annular centrifugal contactors have been developed for tests in the hot cell. The hydraulic performance of both a single-stage centrifugal contactor and a three-stage cascade has been studied. The nominal throughput of the single-stage centrifugal contactor can reach 13.5 l/h under suitable operation conditions for H2O–kerosene system. The hydraulic performance of the three-stage cascade is also good. 相似文献
943.
Xiao Qin Lin Gaoyong Wang Juan Zheng Kaihong Feng Xiaowei 《Protection of Metals and Physical Chemistry of Surfaces》2021,57(1):132-138
Protection of Metals and Physical Chemistry of Surfaces - The effect of pH value on the electroless deposition of copper coated graphite powders (Cu@GPs) was investigated in this paper. The... 相似文献
944.
为了从工艺上提高双金属板成形精度,通过实验结合有限元分析的方法探究了不同工艺参数对成形精度的影响,研究表明:成形角度和成形深度分别是影响底部精度和侧壁精度的最关键因素,当成形角度由30°增大至60°时,底部鼓包高度降低29%,侧壁鼓凸量增加18.5%;当工具头直径由10 mm增大至20 mm时,底部鼓包高度下降13%,侧壁鼓凸量下降16%;当下压量由0.5 mm减小至0.2 mm时,底部鼓包高度下降24%,侧壁鼓凸量增加18.3%;最后优选了合理的工艺参数,使得底面鼓包高度下降49%,侧壁鼓凸量下降41%。 相似文献
945.
A carbon-containing CoCrFeNi high entropy alloy (HEA) with heterogeneous structures was obtained through thermome-chanical treatments,which induced concurrent recrystallization and carbide precipitation in the alloy.A combination of high yield strength (556 MPa) and large uniform elongation (45%) was achieved in the investigated alloy.The enhancement of the strength is attributed to the combined effects of grain refinement,precipitation strengthening and microstructural het-erogeneity.Our work demonstrated that the heterogeneity design could be realized by thermomechanical processes,which provided a practical strategy for producing HEAs with high performance. 相似文献
946.
研究了QT(淬火+回火)和QLT(淬火+临界淬火+回火)热处理对高强结构钢Q690GJ微观组织及低温韧性的影响。通过金相、扫描电镜等方法,对低温冲击试样、无塑性转变试样进行了微观分析。结果表明:QLT工艺处理的Q690GJ钢低温韧性明显优于QT工艺。微观组织分析表明:QLT工艺处理试验钢组织为板条马氏体+残留奥氏体,临界淬火工艺形成了更多数量的、且较为稳定的残留奥氏体软相,提高了起裂前的塑性变形能力;同时形成更多取向混乱的马氏体板条束,有效阻碍了裂纹的扩展,从而提高低温韧性、降低无塑性转变温度。 相似文献
947.
In this paper, a temperature sensor based on the splicing of a core offset multi-mode fiber with two single mode fibers is proposed and demonstrated experimentally. The temperature sensing principle is analyzed and related experiment is performed. By controlling the core offset and splicing length of the specialty multi-mode fiber (SMMF), two sensors with different temperature sensing properties are obtained, and experimental results show that the temperature sensitivity can be up to 48.76 pm/°C in the range of 25—95 °C. Moreover, it has many advantages, including small size, high sensitivity, and simple structure. So it can be used in potential temperature sensing applications, such as industrial production, biomedical science, power electronics, and so on. 相似文献
948.
A dual-band, wide tuning range voltage-controlled oscillator that uses transformer-based fourth-order(LC) resonator with a compact common-centric layout is presented. Compared with the traditional wide band(VCO), it can double frequency tuning range without degrading phase noise performance. The relationship between the coupling coefficient of the transformer, selection of frequency bands, and the quality factor at each band is investigated. The transformer used in the resonator is a circular asymmetric concentric topology. Compared with conventional octagon spirals, the proposed circular asymmetric concentric transformer results in a higher qualityfactor, and hence a lower oscillator phase noise. The VCO is designed and fabricated in a 0.18- m CMOS technology and has 75% wide tuning range of 3.16–7.01 GHz. Depending on the oscillation frequency, the VCO current consumption is adjusted from 4.9 to 6.3 m A. The measured phase noises at 1 MHz offset from carrier frequencies of 3.1, 4.5, 5.1, and 6.6 GHz are –122.5, –113.3, –110.1, and –116.8 d Bc/Hz, respectively. The chip area, including the pads, is 1.20.62 mm2 and the supply voltage is 1.8 V. 相似文献
949.
与广域的互联大电网相比,小型及微型电力系统具有能源综合利用效率高的优点。但小型汽轮机变工况运行频繁,蒸汽参数变化范围大。为了分析蒸汽参数对汽轮机系统稳定性的影响,通过对汽轮机工作机理的研究,建立了汽轮发电机组电磁功率随蒸汽压力变化的数学模型,避免了水蒸气的熵和焓等复杂物理量的测量。研究了蒸汽受限时,汽轮机入口蒸汽压力的变化过程;分析了给定系统在蒸汽受限时的安全稳定域,给出了极限时间与蒸汽受限严重程度、带载量的关系式。该成果对于实际运行中蒸汽受限时的紧急切负荷控制具有重要的指导意义。 相似文献
950.
Fabrication of Transparent Dysprosium Aluminum Garnet (Dy3Al5O12) Ceramics via a Solid‐State Reaction Method 下载免费PDF全文
Song Hu Xianpeng Qin Chunhua Lu Guohong Zhou Zhongzi Xu Shiwei Wang 《Journal of the American Ceramic Society》2015,98(6):1714-1716
Polycrystalline, transparent Dy3Al5O12 ceramics were firstly fabricated by a solid‐state reaction method using high‐purity Dy2O3 and Al2O3 powders. The fully dense Dy3Al5O12 ceramic with an average grain size of less than 10 μm was obtained by vacuum sintering at 1820°C for 6 h. The in‐line transmittance of the optimized sample reaches 80% in the visible region. Scanning electron microscopy reveals that no secondary phases and almost no pores are observed at grain boundaries or triple junctions, and the fracture mode of the ceramic is mainly transgranular. The Dy3Al5O12 ceramic is promising for magneto‐optical applications. Verdet constant of the Dy3Al5O12 transparent ceramic is as high as ?0.41 min·(Oe·cm)?1. 相似文献