简论经济·文化·犯罪的三维机理

在研究犯罪与经济的关系中，笔者长期探索并久久思考的一个问题是：尽管在社会主义市场经济发展的特定历史时期，经济价值规律这只“无形之手”的魔力对于犯罪现象的影响和制约作用已经越来越成为不争的事实。然而，在社会有机体中．支配经济价值规律这只“无形之手”的因素即居于“社会之脑”地位的因素又该是什么呢?笔者认为答案是：文化。也就是说，现代社会中经济犯罪或者刑事犯罪的经济色彩日益浓厚，那么这背后的原因，即导致现代社会特有犯罪形态的支配因素便是文化。

无废城市建设下危险废物风险法律规制论纲——“三维机理”阐释与“三元路径”探索

危险废物及其风险法律规制是无废城市建设的重要环节。“公害性—分摊性—公益性三大特性、责任共同体—命运共同体—利益共同体三大蕴含、伺服原理—自组织原理—协同效应三大原理”,构成危险废物风险法律规制的内在“三维机理”,深层影响危险废物风险法律规制进程。须立足不同类型危险废物、风险意识与认知水平、控制能力等差异,探索其中的“责任层次化、类型化、协同化”三元路径,包括不同层次的责任界定,面源点源化、减量化—资源化—无害化、分层—分次—分步的类型化展开,政府与公众、法律与科技、环境与经济利益等不同层面协同。在生态文明与风险社会时空轴上,积极回应国家(风险)治理体系与治理能力现代化这一时代命题。

Cu-Cr-Zr-Mg合金的相变动力学

通过测量Cu-Cr-Zr-Mg合金样品的导电率,研究了合金的相变动力学。由Avrami经验方程得出了不同时效温度条件下Cu-Cr-Zr-Mg合金的相变动力学方程和电导率方程。通过绘制动力学'S'曲线描述了时效析出规律,并且利用固溶态脱溶分解的积分方程验证了Avrami经验方程描述该合金析出过程的正确性,从而揭示出合金在450~550℃时效时的反应机理是三维扩散控制。450℃×8 h时效时合金的主要析出相为具有cube-on-cube位向关系的有序fcc富Cr相和具有N-W位向关系的B2有序富Cr相。

Simulation analysis on three-dimensional slope failure under different conditions

The failure mechanism of two-dimensional（2D） and three-dimensional（3D） slopes were investigated by using the strength reduction method.An extensive study of 3D effect was conducted with respect to boundary conditions,shear strength and concentrated surcharge load.The results obtained by 2D and 3D analyses were compared and the applicable scope of 2D and 3D method was analyzed.The results of the numerical simulation show that 3D effect is sensitive to the width of slip surface.As for slopes with specific geometry,3D effect is influenced by dimensionless parameter c/（γHtanφ）.For those infinite slopes with local loading,external load has the major impact on failure mode.For those slopes with local loading and geometric constraints,the failure mode is influenced by both factors.With the increase of loading length,boundary condition exerts a more significant impact on the failure mode,and then 2D and 3D stability charts are developed,which provides a rapid and reliable way to calculate 2D and 3D factor of safety without iteration.Finally,a simple and practical calculation procedure based on the study of 3D effect and stability charts is proposed to recognize the right time to apply 2D or 3D method.

基于深度学习的点云目标检测方法

随着自动驾驶技术和点云处理技术的不断发展,如何对点云数据中的点的相关特征进行分析就成为关键问题。针对点云特征分析问题,很多的文献中对点云特征值采取手动输入的方法。然而,该类方法无法适应实际环境中复杂多变的情况。为了解决该问题,该文提出了一种新的基于深度学习网络的三维点云检测框架。该框架以深度学习作为点云分析工具,并引入三维视觉机理,在点云分析时网络会通过已有数据集的训练自动寻找需要注意的点云区域,从而极大地减少了计算成本。在测试时,采用自动驾驶点云数据集对网络进行应用。实验结果表明,与其他三维点云物体检测方法相比,基于深度学习网络的三维点云检测方法能够在对硬件环境要求较低的情况下实现良好的运行效果。

3D stability assessment of stepped slopes in inhomogeneous soils

Stability assessment of slopes has historically been performed assuming soils to be homogeneous in two-dimensional(2D) cases. In real cases, soils are usually inhomogeneous, and each slope collapse indicates a three-dimensional(3D) nature. Based on a 3D rotational failure mechanism, this work develops an approach to account for the impact of the vertical strength inhomogeneity on the 3D stability of stepped slopes. Seismic actions are taken into account by introducing the concept of a horizontal seismic coefficient. An upper-bound expression for stability factors is derived in the light of the kinematic approach, and the most critical solution is obtained from an optimization programming. In comparison with the previously published solutions, the validity of the proposed method is shown. A sensitivity analysis is carried out to discuss parametric effects on the stability of 3D stepped inhomogeneous slopes.

Reliability analysis of supporting pressure in tunnels based on three-dimensional failure mechanism

Based on nonlinear failure criterion,a three-dimensional failure mechanism of the possible collapse of deep tunnel is presented with limit analysis theory.Support pressure is taken into consideration in the virtual work equation performed under the upper bound theorem.It is necessary to point out that the properties of surrounding rock mass plays a vital role in the shape of collapsing rock mass.The first order reliability method and Monte Carlo simulation method are then employed to analyze the stability of presented mechanism.Different rock parameters are considered random variables to value the corresponding reliability index with an increasing applied support pressure.The reliability indexes calculated by two methods are in good agreement.Sensitivity analysis was performed and the influence of coefficient variation of rock parameters was discussed.It is shown that the tensile strength plays a much more important role in reliability index than dimensionless parameter,and that small changes occurring in the coefficient of variation would make great influence of reliability index.Thus,significant attention should be paid to the properties of surrounding rock mass and the applied support pressure to maintain the stability of tunnel can be determined for a given reliability index.

Computerized three-dimensional design system for rectangular tile coating on hull surface

To better guide the coating process of rectangular tiles on a ship hull, a computerized three-dimensional design method is proposed. Research was done on a tile generating algorithm, tile laying design flow, tiles gap examination algorithm, and tiles slight displacement, as well as cutting and rotating algorithms.A three-dimensional design system was developed using an MDT platform. The application of this system indicates that using the design arrangement to coat tiles on a ship’s hull can result in enhanced coating quality.

Modeling mechanistic responses in asphalt pavements under three-dimensional tire-pavement contact pressure

A three dimensional finite element program incorporating actually measured vertical tire-pavement contact pressure(TPCP) was utilized for modeling the mechanistic responses in asphalt concrete(AC) layers by simulating various vehicle motions:stationary and non-stationary(i.e.in acceleration or deceleration mode).Analysis of the results indicated the following items.1) It is critical to use the vertical TPCP as the design control criteria for the tensile strains at the bottom of the AC layer when the base layer modulus is lower in magnitude(e.g.≤400 MPa);however,when the base layer modulus is higher in magnitude(e.g.≥7 000 MPa),the horizontal TPCP and the tensile strains in the X-direction at the surface of the AC layer should also be considered as part of the design response criteria.2) The definition of "overload" needs to be revised to include tire pressure over-inflation,i.e.,a vehicle should be considered to be overloaded if the wheel load exceeds the specification and/or the tire inflation pressure is higher than the specification.3) Light trucks have more structural impact on the strain responses and pavement design when the thickness of the surfacing AC layer is thinner(e.g.≤50 mm).4) The acceleration of a vehicle does not significantly impact the AC surface distresses such as rutting at the top of the upgrade slopes or intersections;however,vehicle deceleration can dramatically induce horizontal shear strains and consequently,aggravate shoving and rutting problems at the highway intersections.Evidently,these factors should be taken into account during mechanistic stress-strain modeling and structural design of asphalt pavements.

Relationship between critical seismic acceleration coefficient and static factor of safety of 3D slopes

Many analytical methods have been adopted to estimate the slope stability by providing various stability numbers,e.g.static safety of factor(static FoS)or the critical seismic acceleration coefficient,while little attention has been given to the relationship between the slope stability numbers and the critical seismic acceleration coefficient.This study aims to investigate the relationship between the static FoS and the critical seismic acceleration coefficient of soil slopes in the framework of the upper-bound limit analysis.Based on the 3D rotational failure mechanism,the critical seismic acceleration coefficient using the pseudo-static method and the static FoS using the strength reduction technique are first determined.Then,the relationship between the static FoS and the critical seismic acceleration coefficient is presented under considering the slope angleβ,the frictional angleφ,and the dimensionless coefficients B/H and c/γH.Finally,a fitting formula between the static FoS and the critical seismic acceleration coefficient is proposed and validated by analytical and numerical results.

Study on mechanism of circumferential cracks in cold-region tunnels

There exists frost damage in cold-region tunnels. The circumferential cracks affect the function of tunnels. Using three-dimensional finite element method, the authors analyzed the mechanism of circumferential cracks in cold-region tunnels It is proved that the internal thermal stress in lining exceeds the tensile strength of concrete, which is the direct cause for circumferential cracks occurring. The laws of thermal stress in lining induced by parameters such as temperature drop, horizontal drag coefficient and length of lining are analyzed. The conclusions are valuable to the design and construction of cold-region tunnels considering the thermal stress.

Experimental Investigations of the Three-DimensionalFlow in a Large Deflection Turbine Cascade with Tip Clearance

Results obtained from an experbontal study of the threedimensional flow survey within and exit of a large defiection linear turbine cascade are presented for a tip clearance levels of 0.08, 1.5, 3.0 percent of chord and compared with the help of boundary layer probes and that within and exit of a blade passage was done with a miniaturised five hole probe. End wall and blade tip surface static pressures were also obtained, in addition to flow visualisation studies. A strong horse-shoe vortex forms in front of the leading edge for zero clearance whereas this vortex does not appear for 3 percent clearance indicating that for large clearance the pressure forces have dominating infiuence than the viscous forces. In addition to normally known clearance vortex, a small tip separation vortex was noticed on the blade tip surface inside the tip gap. Due to the area contraction caused by the tip separation vortex, the fluid movign towards the tip gap from the pressure side is accelerated. Downstream of the vortex, the endwall pressure increases due to flow mixing. Both vortices increase in size and strength along the chord. The miring is incomplete in the aft portion of the blade. The tip gap velocity profiles exhibit wak like characteristics especially at axial positions where the mixing is incomplete. The passage vortex in the present investigations did not diminish with increase in clearance. The discharge coefhcient and the total pressure loss coefficient within the tip gap show similar tendency with lower values near the leading and trailing edge regions.

Blowup mechanism for viscous compressible heat-conductive magnetohydrodynamic flows in three dimensions

We investigate initial-boundary-value problem for three-dimensional magnetohydrodynamic （MHD） system of compressible viscous heat-conductive flows and the three-dimensional full compressible Navier-Stokes equations. We establish a blowup criterion only in terms of the derivative of velocity field, similar to the Beale^Kato-Majda type criterion for compressible viscous barotropic flows by Huang et al. （2011）. The results indicate that the nature of the blowup for compressible MHD models of viscous media is similar to the barotropic compressible Navier-Stokes equations and does not depend on further sophistication of the MHD model, in particular, it is independent of the temperature and magnetic field. It also reveals that the deformation tensor of the velocity field plays a more dominant role than the electromagnetic field and the temperature in regularity theory. Especially, the similar results also hold for compressible viscous heat-conductive Navier-Stokes flows, which extend the results established by Fan et al. （2010）, and I-Iuang and Li （2009）. In addition, the viscous coefficients are only restricted by the physical conditions in this paper.

3D finite element simulation of explosive welding of three-layer plates

A 3D t＇mite element model of the explosive welding process of three-layer plates with materials of steel-copper-copper is es- tablished. Based on the presented model, the bonding mechanism is simulated and analyzed, different detonation modes are also comparatively studied to indicate the driving force spread in few microseconds. The results show that the three layer plates bond together after many times of impact between the flyers and the base driven by detonation wave, which is damping rapidly at each impact with wavelength decreasing. The pressure at the detonation point is minimal, which induces non-bonding of the plates here. Detonation wave propagates in concentric circle both under side-midpoint detonation mode and under center-point detonation mode, but the movement of the flyer is different, which makes non-bonding easily occur at the end of detonation under side-midpoint detonation and at the center of the plate under center-point detonation.

Three-dimensional topological insulators:A review on host materials

In recent years,three-dimensional topological insulators(3DTI) as a novel state of quantum matter have become a hot topic in the fields of condensed matter physics and materials sciences.To fulfill many spectacularly novel quantum phenomena predicted in 3DTI,real host materials are of crucial importance.In this review paper,we first introduce general methods of searching for new 3DTI based on the density-functional theory.Then,we review the recent progress on materials realization of 3DTI including simple elements,binary compounds,ternary compounds,and quaternary compounds.In these potential host materials,some of them have already been confirmed by experiments while the others are not yet.The 3DTI discussed here does not contain the materials with strong electron-electron correlation.Lastly,we give a brief summary and some outlooks in further studies.

Blowup Criteria for Full Compressible Navier-Stokes Equations with Vacuum State

This paper deals with the global strong solution to the three-dimensional(3D)full compressible Navier-Stokes systems with vacuum. The authors provide a sufficient condition which requires that the Sobolev norm of the temperature and some norm of the divergence of the velocity are bounded, for the global regularity of strong solution to the 3D compressible Navier-Stokes equations. This result indicates that the divergence of velocity fields plays a dominant role in the blowup mechanism for the full compressible Navier-Stokes equations in three dimensions.