A phase-field model for deformation twinning

We propose a phase-field model for modeling microstructure evolution during deformation twinning. The order parameters are proportional to the shear strains defined in terms of twin plane orientations and twinning directions. Using a face-centered cubic Al as an example, the deformation energy as a function of shear strain is obtained using first-principle calculations. The gradient energy coefficients are fitted to the twin boundary energies along the twinning planes and to the dislocation core energies along the directions that are perpendicular to the twinning planes. The elastic strain energy of a twinned structure is included using the Khachaturyan's elastic theory. We simulated the twinning process and microstructure evolution under a number of fixed deformations and predicted the twinning plane orientations and microstructures.     

On the detection of time-reversal symmetry breaking by photoemission with circularly polarized light in the high- T c superconductor Bi2212

We argue that that in their recent experiment in which they claim to have found evidence for a time-reversal symmetry broken state, Kaminski et al. () (Nature, 416, p. 610) overlooked small temperature-dependent changes in the superstructure of Bi2212. These subtle changes may manifest themselves by changing the final state configurations of the photoemission process and thus invalidate their ultimate conclusions.     

Crystallization behaviour of Al-based amorphous alloy and nanocomposites by rapid quenching

The microstructure and crystallization behaviour of melt-spun Al₈₈Ni₉Ce₂Fe₁ amorphous alloy and nanophase composites have been studied by means of X-ray diffraction, transmission electron microscopy and scanning and isothermal calorimetry. The diffraction patterns from Al₈₈Ni₉Ce₂Fe₁ amorphous alloys are diffuse, indicating a basically amorphous structure but contain two rings presumed to be associated with quenched-in nuclei. In the cases of Al₈₈Ni₉Ce₂Fe₁ nanophase composites, nanoscale precipitated particles are homogeneously dispersed in an amorphous matrix, and the crystallite diameter and volume fraction are sensitive to quenching conditions. During thermal crystallization, a two-step phase transformation occurs in the amorphous alloy and nanocomposites, which is characterized by a diffusion-controlled precipitation of nanoscale Al particles and the growth of a Al₃(Ni, Fe) nanophase prior to a Al₁₁Ce₃ nanophase. This study gives insight into structure-control for obtaining nanophases dispersed in an amorphous matrix by rapid quenching.     

时态结构中的恒常联系因果学习

人工智能研究中,行动这一概念通常在理论框架中有完全的定义。然而,现实中的行动有时难以完全刻画。智能体需要从过去的经验观察中习得行动的后果。本文提出一种基于时态结构的行动一结果学习理论。在自然数时间结构中,智能体通过观察过去的恒常联系建立因果关系。智能体依据己建立的因果关系指导将来的行动。同时,我们给出关于该理论的一个完全的逻辑演绎系统,并给出基于该逻辑的智能体行动的有效算法。     

Resurgence of goal-directed actions and habits

This study investigated how goal-directed and habitual behaviors recover after extinction within the context of the resurgence effect, a form of relapse induced by the removal or worsening of alternative reinforcement. Rats were trained to press a target lever with one reinforcer (O1) for either minimal (4) or extended (16) sessions. An extinction test after the completion of O1 devaluation confirmed that minimal and extended training formed goal-directed and habitual behaviors, respectively. Then, pressing an alternative lever was reinforced with a second reinforcer (O2) while the target response was placed on extinction. When O2 was discontinued, the minimally trained target response resurged with goal-directed status as in the extinction test. However, the extinguished habitual behavior in the extensively trained rats did not recover as a habit but instead with goal-directed status, possibly due to the context specificity of habits or the introduction of a new response–reinforcer contingency. The critical finding that reinforcer devaluation consistently led to less resurgence regardless of the amount of acquisition training provides a clinical implication that coupling differential-reinforcement-of-alternative-behavior (DRA) treatments with the devaluation of the associated reinforcer of problematic behavior could effectively diminish its recurrence.     

浅析知情同意权在我国立法中的不足

分析了我国在知情同意问题上的法律规则,指出我国现有法律存在四方面的立法缺陷,即对医生同时柯加告知义务与不告知义务,使医生陷入两难处境;在病人同意权方面只要求实验性和特殊诊疗措施征得病人同意,同意的主体上多且乱,过份强调病人家属的同意,侵害或剥夺了病人的自主权;对知情同意权的含义认识不清;知情权与同意权相分离而没有形成完整统一的病人知情同意权,在此基础上,提出完善我国立法的建议。     

非政府组织:一种新的上层建筑形式

非政府组织是与政府组织不同的另一类社会治理组织,属一种新的上层建筑形式。非政府组织与联合国和各国政府部门既有密切联系又持有一定距离,既包括政治倾向较强的组织,也包括非盈利组织。非政府组织迅猛发展的根本原因在于它能有效地解决社会生活中存在着政府失灵和市场所带来的诸多问题,促进社会经济,政治和文化的协调发展,对社会的平衡和安定具有极大的作用。     

中文读写能力及其相关因素的结构模型

运用问卷调查法考查了中文儿童读写能力及其相关因素之间的关系.通过验证性因素分析对量表的信度和效度指标进行了分析,发现量表具有较好的项目信度和结构效度.结构模型分析发现阅读听写能力影响书面语意义理解和书写技能,而书面语意义理解和书写技能对书面表达有显著影响.家庭阅读背景影响儿童的口语能力和阅读听写能力,口语能力影响意义理解和阅读听写能力,基本知觉加工影响口语能力和阅读听写,动作技能影响书写技能.上述结果表明中文字词识别、书写技能和意义理解水平都影响书面表达,即段落产生能力.而口语能力、家庭阅读背景、基本知觉加工和动作技能分别对读写能力的不同侧面产生影响.本研究还分析了模型的年龄和性别特点.     

当代农民价值取向现状的调查研究

本研究测量了来自江苏、福建、山东、辽宁、内蒙古和陕西 6个省份的586名农民的价值取向 ,并对其在年龄、教育水平、省份和婚姻状况等方面的特点进行了分析 ,结果表明 :(1 )中国农民的价值取向总体上是积极向上的 ,他们在重视正义公理、公共利益和法律规范的同时 ,也重视学习工作的重要价值 ;(2 )不同亚群体农民的价值取向之间存在一定的差异。     

文本阅读中简单推理情境下的信息整合

研究采用动窗技术探讨了文本阅读中需要简单推理情境下的信息整合发生的时机。本研究通过三个实验证明了在需要简单推理情境下的文本阅读中 ,需要推理的信息整合是即时发生的 ,而不是经过追溯才发生 ,在这种情况下支持文本阅读的更新追随假设理论。同时本研究发现文本阅读中协调性整合不是以词为单位的。