粒子弱荷的研究(英文)

为了研究有质量的中微子 ,在理论上引入了粒子 (基本费米子、中间玻色子和强子 )弱荷的新概念 .首次报道了弱荷守恒定律 ,并提出了检验弱荷是否存在的实验方案 .根据弱荷的手征性 ,合理地解释了宇称不守恒的原因 .根据弱荷的对称性扩展了标准模型 ,指出所有的中微子都是有质量的Dirac粒子 ,但是右手中微子和左手反中微子的弱荷为零 ,它们不参与弱相互作用 。

费米子的弱荷

从标准模型的中性流出发引入费米子弱荷的新概念，并对它们的性质进行讨论．根据弱荷的对称性，提出所有的中微子都是有质量的，但右手中微子和左手反中微子的弱荷为零，因而不参与弱相互作用．根据弱荷的手征性，合理地解释了弱相互作用中宇称不守恒的原因．

轻子与荷电弱规范玻色子的弹性散射

基于Ｗｅｉｎｂｅｒｇ－Ｓａｌａｍ弱电统一理论，计算了在新粒子态产生阈以下的轻子与荷电弱规范子即Ｗ±玻色子的弹性散射振幅，其中不仅考虑了理论的阿贝尔动力学的贡献，也计算了理论的非阿贝尔动力学的贡献．继而，得到了相应的散射截面角分布，最后对所得结果进行了简短的讨论．

Research on large-scale cascading failure of power systems using synergistic effect

This paper discusses the primary causes from the point of synergistic effects to improve power system vulnerability in the power system planning and safety operation. Based on the vulnerability conception in the complex network theory the vulnerability of the power system can be evaluated by the minimum load loss rate when considering power supply ability.Consequently according to the synergistic effect theory the critical line of the power system is defined by its influence on failure set vulnerability in N-k contingencies.The cascading failure modes are proposed based on the criterion whether the acceptable load curtailment level is below a preset value.Significant conclusions are revealed by results of IEEE 39 case analysis weak points of power networks and heavy load condition are the main causes of large-scale cascading failures damaging synergistic effects can result in partial failure developed into large-scale cascading failures vulnerable lines of power systems can directly lead the partial failure to deteriorate into a large blackout while less vulnerable lines can cause a large-scale cascading failure.

Tunnel failure in hard rock with multiple weak planes due to excavation unloading of in-situ stress

Natural geological structures in rock(e.g.,joints,weakness planes,defects)play a vital role in the stability of tunnels and underground operations during construction.We investigated the failure characteristics of a deep circular tunnel in a rock mass with multiple weakness planes using a 2D combined finite element method/discrete element method(FEM/DEM).Conventional triaxial compression tests were performed on typical hard rock(marble)specimens under a range of confinement stress conditions to validate the rationale and accuracy of the proposed numerical approach.Parametric analysis was subsequently conducted to investigate the influence of inclination angle,and length on the crack propagation behavior,failure mode,energy evolution,and displacement distribution of the surrounding rock.The results show that the inclination angle strongly affects tunnel stability,and the failure intensity and damage range increase with increasing inclination angle and then decrease.The dynamic disasters are more likely with increasing weak plane length.Shearing and sliding along multiple weak planes are also consistently accompanied by kinetic energy fluctuations and surges after unloading,which implies a potentially violent dynamic response around a deeply-buried tunnel.Interactions between slabbing and shearing near the excavation boundaries are also discussed.The results presented here provide important insight into deep tunnel failure in hard rock influenced by both unloading disturbance and tectonic activation.

Stability of submarine slopes in the northern South China Sea: a numerical approach

Submarine landslides occur frequently on most continental margins. They are effective mechanisms of sediment transfer but also a geological hazard to seafloor installations. In this paper, submarine slope stability is evaluated using a 2D limit equilibrium method. Considerations of slope, sediment, and triggering force on the factor of safety （FOS） were calculated in drained and undrained （4=0） cases. Results show that submarine slopes are stable when the slope is 〈16° under static conditions and without a weak interlayer. With a weak interlayer, slopes are stable at 〈18° in the drained case and at 〈9° in the undrained case. Earthquake loading can drastically reduce the shear strength of sediment with increased pore water pressure. The slope became unstable at 〉13° with earthquake peak ground acceleration （PGA） of 0.5 g; whereas with a weak layer, a PGA of 0.2 g could trigger instability at slopes 〉 10°, and 〉3 ° for PGA of 0.5 g. The northern slope of the South China Sea is geomorphologically stable under static conditions. However, because of the possibility of high PGA at the eastern margin of the South China Sea, submarine slides are likely on the Taiwan Bank slope and eastern part of the Dongsha slope. Therefore, submarine slides recognized in seismic profiles on the Taiwan Bank slope would be triggered by an earthquake, the most important factor for triggering submarine slides on the northern slope of the South China Sea. Considering the distribution of PGA, we consider the northern slope of the South China Sea to be stable, excluding the Taiwan Bank slope, which is tectonically active.

Dynamic characteristics of high stressed red sandstone subjected to unloading and impact loads

In the process of deep projects excavation,deep rock often experiences a full stress process from high stress to unloading and then to impact disturbance failure.To study the dynamic characteristics of three-dimensional high stressed red sandstone subjected to unloading and impact loads,impact compression tests were conducted on red sandstone under confining pressure unloading conditions using a modified split Hopkinson pressure bar.Impact disturbance tests of uniaxial pre-stressed rock were also conducted(without considering confining pressure unloading effect).The results demonstrate that the impact compression strength of red sandstone shows an obvious strain rate effect.With an approximately equal strain rate,the dynamic strength of red sandstone under confining unloading conditions is less than that in the uniaxial pre-stressed impact compression test.Confining pressure unloading produces a strength-weakening effect,and the dynamic strength weakening factor(DSWF)is also defined.The results also indicate that the strain rate of the rock and the incident energy change in a logarithmic relation.With similar incident energies,unloading results in a higher strain rate in pre-stressed rock.According to the experimental analysis,unloading does not affect the failure mode,but reduces the dynamic strength of pre-stressed rock.The influence of confining pressure unloading on the shear strength parameters(cohesion and friction angle)is discussed.Under the same external energy impact compression,prestressed rock subjected to unloading is more likely to be destroyed.Thus,the effect of unloading on the rock mechanical characteristics should be considered in deep rock project excavation design.

Variation of cavity gas pressure in slopes with weak intercalation under seismic load

This study discussed how cavity gas pressure affects the stability of rock mass with fractures under well controlled laboratory experiments.Suddenly-created void space created and the induced gas pressures have been the focus of active researches because they are associated with fast movement of large-scale landslides.A shaking table experiment was set up to mimic weak-intercalated rock slope under seismic loads.Excessive cavity gas pressure would be produced in weak spots upon a sudden vibration load.The drastically elevated gas pressure is believed to be responsible for the creation of cavities surrounding the tension fracture.With dissipation of the excessive cavity gas pressure,the fractures are in unbounded closed-state.This observation explains that the slope body would be split and loosened under several aftershocks,and with the expanding of the cracks,the slope failure eventually occurred.The research of the mechanism of cavity gas pressure could provide a novel insight into the formation mechanism of landslides under seismic load and has implications for the disaster prevention and control theory for the slope stability evaluation.

Assessing the vulnerability of Dutch water bodies to exotic species： A new methodology

Invasive exotic （alien） species have not been taken into enough consideration concerning the European Water Framework Directive （WFD） and other European directives until recently. The Dutch ministry responsible for water management is looking for ways to establish the impacts that invasive alien species may have on specified water types. This paper concentrates on the vulnerability of such water types to the introduction of exotic species. This new approach focusses on the system where the alien species are introduced into rather than only on the alien species themselves. We propose an equation that combines threats to and in water types with effects of particular species （observed or prognosticated）. Numerical values used in the formula have been found by scoring a number of properties in different water types and species, which are specified in questionnaires. The results of the calculations are given as relative vulnerability scores （scale 1-10）. By testing as many as 8 water types and 13 species, we demonstrate that this method is flexible and easy to use for water managers. Our results can be translated into classes of vulner- ability, which are represented on geographical maps with colour codes to indicate different degrees of vulnerability in the different water bodies. This readily corresponds to the way countries are required to report to the European Union in the context of the WFD. The method can also be generalized using functional groups of （exotic） species instead of particular species