淮安芒硝资源开发现状与发展对策

淮安芒硝资料的开发利用已使基我国东部新崛起的开采与加工基地，但问题也随之逐渐显现出来，主要是缺乏通盘规划、盲目扩大生产规模、污染环境以及勘查和基础设施跟不上等。就以上问题，作者对淮安芒硝开发提出了相应的对策与建议。     

Grain size reduction by dynamic recrystallization: can it result in major rheological weakening?

It is widely believed that grain size reduction by dynamic recrystallization can lead to major rheological weakening and associated strain localization by bringing about a switch from grain size insensitive dislocation creep to grain size sensitive diffusion creep. Recently, however, we advanced the hypothesis that, rather than a switch, dynamic recrystallization leads to a balance between grain size reduction and grain growth processes set up in the neighborhood of the boundary between the dislocation creep field and the diffusion creep field. In this paper, we compare the predictions implied by our hypothesis with those of other models for dynamic recrystallization. We also evaluate the full range of models against experimental data on a variety of materials. We conclude that a temperature dependence of the relationship between recrystallized grain size and flow stress cannot be neglected a priori. This should be taken into account when estimating natural flow stresses using experimentally calibrated recrystallized grain size piezometers. We also demonstrate experimental support for the field boundary hypothesis. This support implies that significant weakening by grain size reduction in localized shear zones is possible only if caused by a process other than dynamic recrystallization (such as syntectonic reaction or cataclasis) or if grain growth is inhibited.     

Neo-deterministic definition of seismic input for residential seismically isolated buildings

This paper deals with the neo-deterministic definition of the seismic input in the municipality of Nimis (Italy), aimed at the design of residential seismically isolated buildings. The seismic input is defined by the computation of realistic synthetic seismograms considering different levels of detail for the earthquake source, both for a bedrock model and taking into account the specific site conditions. The horizontal response spectrum, calculated in the centre of the municipality by modelling the most dangerous source, advises against the construction of a building with a fixed base, but it is compatible with the seismic isolation, and it has been, therefore, used for the design of a residential seismically isolated building. The maximum displacement for the isolation system has been estimated about 17 cm, a value much lower than that provided by the code design response spectrum (28 cm). The importance of the realistic modelling, which permits the generalization of empirical observations by means of, physically sound, theoretical considerations, is evident, as it allows for the optimisation of the structural design with respect to the site of interest.     

Landslides types controlled by tectonics-induced evolution of valley slopes (Northern Apennines,Italy)

This paper investigates the role played by geomorphological and tectonic processes affecting a portion of an active mountain belt in causing the occurrence of different types of landslides developed in flysch bedrock. The adopted multidisciplinary approach (geomorphology, geology and geophysics) allowed to recognize in a portion of the Northern Apennines of Italy different types of landslides that developed in response to slope dynamics, in turn dependent on broader regional-scale tectonic processes. Sedimentary bed attitude, local tectonic discontinuities and lithology only partially influenced the type of landslides, which have been deeply affected by the activity of regional-scale antiform that controlled the hillslope geomorphic evolution in different ways. The growth of this structure and the tilting of its forelimb produced gently dipping slopes that approached the threshold angle that can cause the occurrence of (mainly) translational rockslides. Conversely, high-angle normal faulting parallel to the antiform axis (related to a later stage of activity of the antiform itself) strongly controlled the stream network evolution and caused the watercourses to deeply incise portions of their valleys. This incision produced younger steep valley slopes and caused the development of complex landslides (roto-translational slides-earth/debris flow). The results of the integrated study presented in this paper allowed to distinguish two main types of landslides whose development reflects the events that led to the geomorphological and geological evolution of the area. In this perspective, within the study area, landslides can be regarded and used as indicators of broader-scale recent tectonic processes.     

Reply to “Discussion 1 on ‘Introspection on improper seismic retrofit of Basilica Santa Maria di Collemaggio after 2009 Italian earthquake' by G.P.Cimellaro, A.M.Reinhorn and A.De Stefano” by Vincenzo Ciampi

The authors thank the discusser for his interest and careful review of the paper and his valuable comments.They also welcome this discussion,because it gives the authors the opportunity to clarify several points which were not explained in sufficient detail in the paper,due to space limitations. The paper does not provide any personal or professional criticism of the discusser or his work and if any statement may have raised an ambiguous interpretation,this should be clarified and dismissed.Any inaccuracy in the reference's citation was not intentional.Some of the authors do not speak Italian;therefore they could not read directly and understand the paper cited by the discusser,which is in Italian.     

Unit-pockmarks and their potential significance for predicting fluid flow

Unit-pockmarks were recognized as more-or-less insignificant features on the seafloor in the early 1980s. However, this investigation, at four different regions in Norwegian waters, suggests they are more significant for seep detection than previously believed. They occur as circular depressions in the seafloor (diameter < 5 m) either as singular features, as strings, or as clusters. One of our main conclusions is that they are widespread and represent the most recent and most active local seep locations. This is based on their areal density distribution, the finding of relatively high hydrocarbon concentrations inside sampled unit-pockmarks and at locations where they are abundant, and on theoretical considerations. When unit-pockmarks occur together with ‘normal-sized’ pockmarks, they often form to the side of the normal-pockmark centre. Our study also suggests that (1) the driving force behind seafloor hydraulic activity, i.e., the formation of unit-pockmarks, normal-pockmarks, and many other fluid flow features, is pockets of buried free gas, and (2) whereas unit-pockmarks likely manifest cyclic pore-water seepage, their larger related, normal-pockmarks, likely manifest periodic or intermittent gas bursts (eruptions), with extended intervening periods of slow, diffusive, and cyclic pore-water seepage. Our findings suggest that seep detection is most efficiently performed by mapping the seafloor with high-resolution bathymetry (at least 1 m × 1 m gridding), and acquiring geochemical samples where the density of unit-pockmarks is locally highest.     

安徽黄山地区侏罗纪—白垩纪层序地层学特征

通过 1∶ 5万区域地质调查工作对屯溪—休宁盆地、歙县洪琴盆地、绩溪华阳盆地、祁门盆地各类陆相沉积建造的沉积环境、沉积相、陆相沉积体系域进行了分析描述 ,将侏罗纪—白垩纪地层划分为四级地层层序 ,在层序地层学分析的基础上 ,建立了初步的红盆地层格架     

Optimal design and seismic performance of tuned mass damper inerter (TMDI) for structures with nonlinear base isolation systems

The tuned mass damper inerter (TMDI) couples the classical tuned mass damper (TMD) with an inerter, a mechanical device whose generated force is proportional to the relative acceleration between its terminals, thus providing beneficial mass‐amplification effects. This paper deals with a dynamic layout in which the TMDI is installed below the isolation floor of base‐isolated structures in order to enhance the earthquake resilience and reduce the displacement demand. Unlike most of the literature studies that assumed a linearized behavior of the isolators, the aim of this paper is to investigate the effectiveness of the TMDI while accounting for the nonlinearity of the isolators. Two nonlinear constitutive behaviors are considered, a Coulomb friction model and a Bouc‐Wen hysteretic model, representative of friction pendulum and of lead‐rubber‐bearing isolators, respectively. Optimal design is based on the stochastic dynamic analysis of the system, by modeling the base acceleration as a Kanai‐Tajimi filtered stationary random process and resorting to the stochastic linearization technique to handle the nonlinear terms. Different tuning criteria based on displacement, acceleration, and energy‐based performance indices are defined, and their implications in a design process are discussed. It is proven that the improved robustness of the TMDI reduces its performance sensitivity to the tuning frequency and to the earthquake frequency content, which are well‐known shortcomings of TMD‐like systems. This important feature makes the TMDI particularly suitable for nonlinear base‐isolated structures that are affected by unavoidable uncertainties in the isolators' properties and that may experience changes of isolators effective stiffness depending on the excitation level.