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941.
对常见的一个精细化工专业及高分子专业实验-聚醋酸乙烯酯乳液合成实验进行了探索,通过对反应温度、保护胶体种类、乳化剂种类与配比等条件的对比及优化,选取了更合适的原料及更优的工艺条件,使学生在实验过程中更易于掌握,制备出的乳液的稳定性及粘度都得到明显改善。 相似文献
942.
Metal spinning is a plastic forming process in which a disk or tube of metal is rotated at high speed and forced onto a mandrel. It is widely used in industry as an efficient, modern and economical production technique. This research proposes to develop a versatile robotic forming method and expand the application areas of robotic manufacturing processes to the metal spinning area. A lathe-type laboratory setup has been built and an industrial robot manipulator has been used to implement the metal spinning process. Experiments have been conducted with enhanced cascaded trajectory tracking algorithms with an add-on vibration suppressor. The potential of the proposed method has been illustrated with extensive case studies using both constant and variable speed trajectory profiles. Analyses for the growth of wrinkles have been performed through the topographical measurements of the products and the forming forces have been inspected. Results indicate that the efficiency of the process can be significantly improved with suitably selected variable speed trajectory profiles and the process parameters. The developed scheme successfully reduces the excessive oscillations of the manipulator during the metal spinning process and it requires no additional hardware to employ. The investigations demonstrate the feasibility of robotic metal spinning using an industrial serial link manipulator. 相似文献
943.
Phosphorescent OLEDs: Sky‐Blue Phosphorescent OLEDs with 34.1% External Quantum Efficiency Using a Low Refractive Index Electron Transporting Layer (Adv. Mater. 24/2016)
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944.
《Energy Policy》2016
A fundamental policy design choice in government-led climate change mitigation is: what role should flexibility mechanisms like carbon offsetting play in reducing greenhouse gas (GHG) emissions. Since public opinion affects the policy choices of government, we investigate how arguments regarding carbon offsetting's economic efficiency, effectiveness, and ethicality, which have been key points in the public debate, impact the public's preferences. We fielded an online framing experiment in the United States (N=995) to empirically identify how arguments for and against carbon offsetting influence public preferences for the inclusion of offsetting in national GHG mitigation policy. We find that the public's support for international offsetting increases and support for reductions at their source (i.e. within firms' own operations) diminishes when considerations of economic efficiency gains are at the forefront. Support for offsetting declines when individuals are confronted with arguments concerning its effectiveness and ethicality, which suggests that future policies will require clear standards of additionality in order to address these concerns. Moreover, we find that how carbon offsetting is framed matters even amongst climate skeptics and support could potentially be enhanced via improved communication on efficiency gains. 相似文献
945.
This paper presents a new approach to assess time-dependent corrosion fatigue damage of welded joint considering the coupling effect between mechanical factor and corrosion factor. The high stress region around weld will accelerate corrosion and be more likely to induce nonuniform corrosion of welded joint. And the effect of loading on corrosion behavior of the steel in NaCl solution was investigated. The synergistic effect between applied elastic stress and chemical attack on Q235 steel was evaluated by electrochemical experiments. A side longitudinal of ship structure is selected as a case study. Time-dependent stress concentration factor of welded joint as a function of corrosion deterioration was analyzed, and the iterative process of stress and corrosion degeneration of plate thickness was used to simulate coupling effect basing on the results of experiment. The hot spot stress approach was adopted to calculate the fatigue damage. It is revealed that the nonuniform corrosion could influence fatigue damage of welded joint, and that impact will be more and more significant with the growth of corrosion year. 相似文献
946.
Pairwise Meta-Modeling of Multivariate Output Computer Models Using Nonseparable Covariance Function
Yongxiang Li 《技术计量学》2016,58(4):483-494
Gaussian process (GP) is a popular method for emulating deterministic computer simulation models. Its natural extension to computer models with multivariate outputs employs a multivariate Gaussian process (MGP) framework. Nevertheless, with significant increase in the number of design points and the number of model parameters, building an MGP model is a very challenging task. Under a general MGP model framework with nonseparable covariance functions, we propose an efficient meta-modeling approach featuring a pairwise model building scheme. The proposed method has excellent scalability even for a large number of output levels. Some properties of the proposed method have been investigated and its performance has been demonstrated through several numerical examples. Supplementary materials for this article are available online. 相似文献
947.
948.
Toshihiko Yamaguchi Ovidiu Mihalache 《Journal of Nuclear Science and Technology》2017,54(11):1201-1214
A new design has been adopted for the steam generator (SG) tubes of the Japan Sodium-cooled Fast Reactor (JSFR) using double-wall tubes. This paper estimates and assesses the effectiveness of detecting defects in SG double-wall tubes of the JSFR by using combined high-frequency eddy current testing (ECT) and low-frequency remote field eddy current sensors. We confirm that the proposed hybrid ECT sensor is highly sensitive to small defects, fatigue cracks, and other defects even when located under support plates of tubes. The parameters of the hybrid ECT sensor are designed and optimized to detect small defects using accurate numerical simulations based on the finite element method, using an in-house developed code. The sensitivity and high performance of the hybrid ECT sensor was validated with experimental measurements. 相似文献
949.
异形内套加工时,原使用的工艺是车削加工或冷镦加工或一般冲压加工3种。这几种工艺加工成本过高,从而影响市场竞争。对一般的冲压加工增加制件塑性变形保护机构后,解决了脱模难这一大难题。该模具结构设计方法,旨在使设计人员理清模具设计思路与步骤,提高模具设计的水平和工作效率。希望对模具设计人员有一定的帮助和指导作用。 相似文献
950.