中国城乡社会结构性断裂引发的体育产业城乡布局思考

运用文献资料、比较分析等方法,从产业经济学的产业结构层面,分析中国社会的城乡结构性断裂给体育产业发展带来的影响。中国社会出现了结构性断裂的问题:人们的经济水平、社会地位、生活方式、价值观念等都带有明显的时代性差异。这些差异使得不同部分人群从事体育活动的主客观条件产生了不同。客观方面,人们拥有或从事体育活动的物质技术条件、生产和生活方式等条件存在巨大差异;主观方面主要是造成了人们对于体育的需求和价值观的不同。通过分析得出:在中国城乡社会二元结构性断裂状况未得到根本改变的情况下,以自然经济为主要特征的中国乡村社会是不具备发展现代体育的现实条件的,中国体育产业发展的城乡布局问题,不应该把重点放在农村,如果把体育产业结构按照城乡结构分类的话,城市应该占较大的比重,农村占较小的比重。

有关硬件紧固件结构性断裂隐患的常识及评估方法

硬性紧固件结构性断裂的问题并不常见,但有时会突然发生,事先无预兆。一旦结构性断裂发生,可能造成极为严重、甚至是灾难性的后果。本文介绍了符合行业标准的双硬度紧固件产品,而并非有缺陷的硬性紧固件结构性断裂的条件,并对造成硬件紧固件结构性断裂产生的原因进行了详尽的阐述。

农民工子弟适应行为与群体亚文化——北京市W农民工子弟学校学生亚文化的一个解释框架

通过对“W校”班级日常的调查,总结了在学校规训权力下,学生亚文化的表现形式,包括作为“抵抗”的“反学习、反规范文化”、实现个人归属感的“小集团文化”和被主流制度“收编”的“积分交换文化”。社会和学校为学生设定了“分数至上”的目标,但并未在制度上为其提供实现该目标的有效手段。在默顿的紧张理论视域下,这种目标与手段的结构性断裂导致了学生的认同危机。学生通过建构一系列适应行为(遵从、敷衍、抵制、对抗)以缓解焦虑,进而形成了独特的群体亚文化。学校教师通过“素质评价”对“子弟们”加以标签化,加剧了“既定目标”与“实现手段”的背离。为改善农民工子弟的受教育情况,实现教育公平,需要社会各界共同努力,协作完成。

Transition of plasticity and fracture mode of Zr-Al-Ni-Cu bulk metallic glasses with network structures

Effect of network structure on plasticity and fracture mode of Zr？Al？Ni？Cu bulk metallic glasses （BMGs） was investigated. The microstructures of transversal and longitudinal sections were exposed by chemical etching and observed by scanning electron microscopy （SEM）. The mechanical properties were examined by room-temperature uniaxial compression test. The results show that both plasticity and fracture mode are significantly affected by the network structure and the alteration occurs when the size of the network structure reaches up to a critical value. When the cell size （dc） of the network structure is ~3μm, Zr-based BMGs characterize in plasticity that decreases with increasingdc. The fracture mode gradually transforms from single 45° shear fracture to double 45° shear fracture and then cleavage fracture with increasingdc. In addition, the mechanisms of the transition of the plasticity and the fracture mode for these Zr-based BMGs are also discussed.

The effect of plastic constraint on the initiation of ductile tears in shipbuilding structural steels

In this paper, the effect of plastic constraint on the initiation of ductile tears in four different shipbuilding structural steels has been experimentally studied by measuring the J-integral and crack opening displacement COD at initiation in three-point bend specimens with deep and shallow notches. Experimental results of seven groups of different strength alloy steels show that both Si and Ji values of ductile tear from the shallow crack specimens which have less constraint flow field are significantly higher than those of deeply notched specimens. Slip-line-field analysis shows that, for shallow crack, the hydrostatic stress is lower than that from standard deeply cracked bend specimen, which develops a high level of crack tip constraint, provides a lower bound estimate of toughness, and will ensure an unduly conservative approach when applied to structural defects, especially if initiation values of COD and J-integral are used.

Mechanical properties and fracture mechanism of as-cast MnFeCoCuNix high-entropy alloys

MnFeCoCuNix high-entropy alloys(HEAs)with different Ni contents were fabricated by vacuum induction melting.XRD and SEM−EDS were used to analyze the phase constitution and structure,and the tensile properties of the samples were determined using a universal tensile tester.The results show that the HEAs consist of a dual-phase structure,in which FCC1 phase is rich in Fe and Co,while the FCC2 phase has high contents of Cu and Mn.As Ni content increases,the segregation of Cu decreases,accompanied by the decrease of FCC2 phase.Moreover,the tensile strength of the HEAs increases first and then decreases,and the elongation increases slightly.This is attributed to the combined effect of interface strengthening and solid solution strengthening.The in-situ stretched MnFeCoCuNi0.5 alloy shows obvious neck shrinkage during the tensile fracture process.In the initial deformation stage,the slip lines show different morphologies in the dual-phase structure.However,in the later stage,the surface slip lines become longer and denser due to the redistribution of atoms and the re-separation of the dissolved phase.

Microstructural evolution and mechanical properties of new multi-phase NiAl-based alloy during heat treatments

Microstructural evolution and the relationship between microstructure and property during heat treatments in a new NiAl-based alloy(Ni-26.6Al-13.4Cr-8.1Co-4.3Ti-1.3W-0.9Mo,molar fraction,%))were investigated.The as-cast alloy is composed of NiAl matrix and Cr3Ni2 phase with poor ductility.The Cr3Ni2 phase is distributed as a network along the NiAl grain boundaries.Subsequent heat treatment(1 523 K,20 h,air cooling+1 123 K,16 h,furnace cooling)leads to the dissolution of Cr3Ni2 phase and the precipitation of lath-shaped Ni3Al phase andα-Cr particles,resulting in the improvement of compressive properties and fracture toughness at room temperature.Followed by long-term thermal exposure(1 173 K,8 500 h),it is found that the residual Cr3Ni2 phase keeps stable while theα-Cr particles coarsen and a great mass of lath-shaped Ni3Al precipitates are degenerated,which compromises most of the above improvements of mechanical properties through heat treatment.

Discussion on the Seismogenic Fault of the 1976 Tangshan Earthquake

The opinions of two papers carried in the journal "Seismology and Geology" are discussed in the paper.One is that the Tangshan fault is a high-angle,west-dipping and thrust with strike-slip fault.The other is that the Fuzhuang-Xihe fault distributed on the east side of Tangshan city is the seismogenic fault that caused the Tangshan earthquake.For the former opinion,it needs to explain the relationship between the active style of the thrust Tangshan fault and the formation genesis of a Quaternary depression along the west side of Tangshan city.For the latter opinion,if the Fuzhuang-Xihe fault is the seismogenic fault of the Tangshan earthquake,it needs to explain the genesis relationship between this west-dip slip fault zone and the strike-slip surface fissure zone that extends through Tangshan city.And it needs more evidence exclude the possibility that the surface rupture belongs to the rupturing of a secondary structure.This paper suggests doing more work on the active fault that controls the Caobo Quaternary depression.

Prospects and Current Studies on the Fault Zone Seismic Waves

Deep structure and material properties of faults can be understood by observing and simulating the particular phase in a fault fracture zone. This paper reviews the development of fault-zone seismic waves in the seismological domain. The present research status of fault-zone head wave and trapped wave are summarized systematically. Based on recent progress in this field,the paper discusses the prospect on the utilization of seismic wave in fault structure research.