Results 21 to 30 of about 31,003 (237)
Theoritical investigations of structural stability, mechanical and thermodynamics properties for γ’ precipitates in Co-based superalloys [PDF]
, 2015 随着国防科技的迅猛发展，新一代的航空航天飞机对发动机涡轮叶片材料的承温能力提出更高的要求。传统Ni基高温合金由于熔点的限制，其最高使用温度已不能满足需要。寻找下一代新型高温合金以满足发展更高效率航空发动机的需求是国内外学术界和产业应用领域共同关注的焦点。最近，新型γ’析出相强化型Co基合金的发现在全世界掀起了开发新型钴基高温材料的热潮。类似于γ’-Ni3Al，γ’析出相在新型Co基高温合金中起到了至关重要的作用。γ’相的结构稳定性、弹性力学性质与温度的依存关系直接决定了Co基合金在高温下的性能表现 ...
许伟伟
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Risk, Hazards &Crisis in Public Policy, EarlyView.Abstract Norway's oil sector faces significant security challenges due to rapid technological advancements and heightened geopolitical tensions, particularly concerning threats from Russian drones. The sector maintains a vigilant approach, continually monitoring and adapting to evolving threats.
Riana Steen, Tommy B. Hansen
wiley +1 more source
Zhongguo cuzhong zazhi, 2018 目的 探讨以问题为基础学习（problem-based learning，PBL）教学法在神经内科进修医师急性脑血管 病合并癫痫发作教学过程中的应用价值。 方法 选取首都医科大学附属北京天坛医院神经内科进修医师24名为教学对象，采用随机数字表将 其分为PBL教学组和传统教学组。在急性脑血管病合并癫痫发作的诊断和治疗方案确定过程中分别 对两组采用PBL教学法和传统教学法，以问卷调查的方法对两组的教学效果进行评价。 结果 PBL教学组与传统教学组相比，进修医师在自主学习能力、提出问题能力、解决问题能力、临 ...
吕瑞娟，王群
doaj +1 more source
, 2006 对于宏观材料的力学性能的研究通常基于传统的连续介质力学;然而,当研究对象小到微/纳米尺度时,材料缺陷等因素对微观材料力学性能影响程度将不同于宏观材料。此时,材料将表现出明显的尺度效应等力学性能。用传统连续介质理论将不能解释此现象。因此,许多学者基于正问题思想对微观材料的力学性能进行研究:Fleck-Hutchinson提出了机遇传统弹塑性理论的塑性应变梯度理论;Nix-Gao提出了基于位错理论的塑性应变梯度理论;Gerberich等提出了基于比表面能的微尺度材料尺度效应理论[3 ...
舒思齐, 魏悦广
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Fabrication and properties of PVA-TiO2 hydrogel composites [PDF]
, 2012 The preparation and properties of PVA-TiO2 hydrogel composites have been studied in this research. The results show that tensile strength and compression modulus of PVA-TiO2 hydrogel composites increased significantly, but the elongation did not changed ...
Dong, Shijie +3 more
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Risk, Hazards &Crisis in Public Policy, EarlyView.Abstract The current body of multidisciplinary literature on crisis management still has some unresolved problems. This paper focuses on the following four “controversial issues” in dealing with crises: the usefulness of emergency plans; early signal detection; decision‐making amid high uncertainty; and the centralization/decentralization dilemma.
Giliberto Capano, Federico Toth
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2013 单层球面和柱面网壳结构的承载能力已有不少研究,但双层球面网壳的力学特性和失效机理的研究很少涉及。基于此,系统地研究了4种不同矢跨比双层凯威特球面网壳的失效机理和破坏过程,考察了多个力学指标来评估网壳的力学性能,如变形能力、总应变能、总弹/塑性应变能和屈服杆件数等。捕捉了4种矢跨比网壳的杆件失效过程和失效机理的差异。计算结论可为双层球面网壳结构的设计提供参考与借鉴。
李会军, 王正中
doaj
Investigation on optimal thermoeconomic and thermodynamic performances of the refrigeration cycles using ferromagnetic or Gd-based material as the working substance [PDF]
, 2016 当今社会，能源紧缺和环境污染问题日益突出，探寻节能环保的新制冷技术正吸引着越来越多的注意力。具有高效节能、绿色环保、噪音小、结构紧凑的室温磁制冷技术是一种很有潜力的新一代制冷技术的备选。目前，室温磁制冷仍有几大指标需要突破。一是提高制冷机的制冷功率，二是提高制冷机的制冷温跨，三是提高制冷机的热经济性能。当今室温磁制冷发展的两大方向：其一是探索具有高磁热特性的室温磁制冷材料，其二是研制制冷性能指标优的室温磁制冷机。本学位论文是要在提高室温磁制冷机循环的热力学性能和热经济性能方面作出新的有益贡献 ...
徐志超
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Z-direction Enhancing Manufacturing Strategy for 3D Printing Prosthetic Socket of Continuous Fiber Composite [PDF]
, 2022 The prosthetic socket is a necessary rehabilitation-aid equipment for lower limb amputees. As an important kind of human-machine interface between the residual limb and the prosthesis, the prosthetic socket plays an important role in containing the ...
Li, D +7 more
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Exploring Challenges and Opportunities in International Healthcare Partnerships: A Thematic Analysis
World Medical &Health Policy, EarlyView.ABSTRACT In global health collaborations, countries of all development levels may seek international assistance, emphasizing trust and conflict resolution. However, existing frameworks lack sustainability metrics, governance, and evaluation criteria.
Salma Arabi +2 more
wiley +1 more source