岩石中集中装药爆炸能量分布的计算

文中分析了岩石中集中装药爆炸破坏过程,计算了爆破过程所消耗的各种能量的分布。计算结果表明:岩石中2~#岩石铵梯炸药集中药包爆炸时所产生的爆炸气体膨胀能量、冲击波能量分别占装药总能量的50％～60％和10％～20％,无用能约占20％～30％。     

岩石集中装药爆炸能量分布的计算

文中分析了岩石中集中装药爆炸破坏过程，计算了爆破过程所消耗的各种能量的分布。计算结果表明：岩石中２＃岩石铵梯炸药集吕药包爆炸时所产生的爆炸气体膨胀能量，冲击波能量分别占装药能量５０％－６０％和１０％－２０％，无用能约占２０％－３０％。     

基于炮孔不同耦合介质的孔壁爆炸载荷及比能时间函数分析

为从炮孔装药耦合介质的选取上改善爆破效果和控制爆破振动危害,应用爆炸力学的相关理论建立耦合装药、不同耦合介质（水、空气、泥土）装药条件下孔壁爆炸载荷和透射比能的计算方法,通过MATLAB编程计算得到岩石介质中炮孔孔壁爆炸载荷和透射比能的时间函数并作图比较分析。研究表明：耦合装药时,孔壁爆炸载荷的初始值最大,但是衰减也最快;水不耦合装药时,孔壁爆炸载荷的初始值次之,但衰减速度最慢,作用时间最长;水不耦合装药时,孔壁透射比能量最大,耦合装药时次之;空气和泥土不耦合装药孔壁爆炸载荷与透射比能均较小。因此水不耦合装药提高了能量利用率,更有利于改善爆破效果,但产生的爆破振动强度大、作用时间长,不利于爆破振动危害控制。     

掏槽爆破爆炸能量与损伤岩体破坏的能量匹配

对掏槽爆破的本质进行了探讨,指出掏槽爆破中岩石的开裂、破碎以及高温高压下的团结都是装药爆炸所释放的能量与岩石自身损伤状态匹配的结果,同时也给出了发生这些现象所必须满足的匹配条件。     

岩石中爆炸应变波信号测试与分析

针对岩石爆破过程中爆炸应变波信号易失真、难测试的特点,建立了一套稳定可靠的超动态应变测试系统.实测了小药量耦合装药在岩石模型中爆炸产生的径向爆炸应变波信号,得到了装药爆炸应变波形的特点以及应变峰值与药包长径比、药量、相对距离的变化关系.试验结果表明:(1)岩石爆破过程中爆炸波综合作用时间约为10μs,表现出初始以压应力为主,持续的压、拉应力交替现象,爆炸加载应变率以104 s-1的数量级变化;(2)药包长径比和药量的变化对应变峰值变化幅度影响在爆源近距离处较大,在相对距离大于45后影响较小;(3)长径比大的药包的爆炸能量对介质作用较为分散,有利于提高炸药的能量利用率.     

装药位置对震塌高度的影响

装药位置对爆炸作用有重要影响,是爆炸工程和战斗部终点效应研究中的课题之一。本文通过数值计算来模拟半无限的岩石介质中炸药对在地下的10m处拱形工事的毁伤情况。研究了在相同装药质量情况下装药位置对毁伤情况的影响,得到地下爆炸载荷下岩石工事周围的动力学响应,以及装药为2kg、爆源距工事顶端分别为3、5、7m时爆炸对工事顶部产生的塌落高度。     

装药位置对震塌高度的影响

装药位置对爆炸作用有重要影响,是爆炸工程和战斗部终点效应研究中的课题之一。本文通过数值计算来模拟半无限的岩石介质中炸药对在地下的10m处拱形工事的毁伤情况。研究了在相同装药质量情况下装药位置对毁伤情况的影响,得到地下爆炸载荷下岩石工事周围的动力学响应,以及装药为2kg、爆源距工事顶端分别为3、5、7m时爆炸对工事顶部产生的塌落高度。     

轴向不耦合装药结构形式优化仿真研究

为了改变某隧道平导爆破效果差、爆炸能量利用率低的现状,采用ANSYS/LS-DYNA模拟不同轴向不耦合装药结构形式对爆破效果的影响,优化装药结构,以期达到增强爆破效果,降低粉尘量和岩石大块率的目的。合理的选择数值模拟中的材料模型和算法,是高效模拟分析轴向不耦合装药结构爆破的关键,因此采用ALE算法对孔口空气填塞不耦合,孔口炮泥填塞、上部空气间隔不耦合,孔口水介质填塞、底部水介质间隔不耦合,孔口炮泥填塞、上部水介质间隔不耦合,孔口水介质填塞、中部水介质间隔不耦合和孔口炮泥填塞与中、上部水介质间隔不耦合的装药结构进行数值模拟,并以爆炸应力波云图和最大拉应力来评价炸药爆破效果。数值模拟结果表明:水介质可以降低炮孔壁附近岩石的压力。装药长度1.25m时,孔口炮泥填塞、上部空气间隔不耦合装药结构较孔口空气填塞不耦合装药结构,能提高爆炸能量的利用率;孔口水介质填塞、底部水介质间隔不耦合装药结构和孔口炮泥填塞、上部水介质间隔不耦合装药结构,爆炸能量利用率基本相同;孔口水介质填塞、中部水介质间隔不耦合装药结构的炸药爆炸能量利用率较其余5种装药结构都大,能提高爆炸应力波对岩石的作用,使得爆炸应力波更加均匀作用于岩体,降低大块率产生。此数值模拟结果可为现场爆破方案设计与实施提供依据。     

轴向不耦合装药结构形式优化仿真研究

为了改变某隧道平导爆破效果差、爆炸能量利用率低的现状,采用ANSYS/LS-DYNA模拟不同轴向不耦合装药结构形式对爆破效果的影响,优化装药结构,以期达到增强爆破效果,降低粉尘量和岩石大块率的目的。合理的选择数值模拟中的材料模型和算法,是高效模拟分析轴向不耦合装药结构爆破的关键,因此采用ALE算法对孔口空气填塞不耦合,孔口炮泥填塞、上部空气间隔不耦合,孔口水介质填塞、底部水介质间隔不耦合,孔口炮泥填塞、上部水介质间隔不耦合,孔口水介质填塞、中部水介质间隔不耦合和孔口炮泥填塞与中、上部水介质间隔不耦合的装药结构进行数值模拟,并以爆炸应力波云图和最大拉应力来评价炸药爆破效果。数值模拟结果表明:水介质可以降低炮孔壁附近岩石的压力。装药长度1.25m时,孔口炮泥填塞、上部空气间隔不耦合装药结构较孔口空气填塞不耦合装药结构,能提高爆炸能量的利用率;孔口水介质填塞、底部水介质间隔不耦合装药结构和孔口炮泥填塞、上部水介质间隔不耦合装药结构,爆炸能量利用率基本相同;孔口水介质填塞、中部水介质间隔不耦合装药结构的炸药爆炸能量利用率较其余5种装药结构都大,能提高爆炸应力波对岩石的作用,使得爆炸应力波更加均匀作用于岩体,降低大块率产生。此数值模拟结果可为现场爆破方案设计与实施提供依据。     

矩形装药在控制断裂爆破中的作用

文中根据实验和数值分析结果,阐述了2号岩石铵梯矩形装药用于小直径炮孔(42mm)控制断裂爆破技术的可能性及合理性;介绍了2号岩石铵梯矩形装药传爆性能和爆炸作用过程的实验结果;探讨了矩形装药孔壁爆炸作用的数值分析方法.     

燃烧合成动力学参数的研究进展

系统地总结了燃烧合成反应动力学参数研究的最新进展、各种相关的唯象模型以及具体的实验方法,归纳了采用各种研究方法得出的表现激活能,并对燃烧合成动力学参数研究的模型进行了评述。     

整数量子霍耳效应和电阻标准

本文介绍新的电阻标准，阐述量子霍尔效应的基本原理，运用朗道能级和局域态等慨念解释二维电子气体在低温和强磁场下的行为．     

Energy Efficient Resource Allocation Approach for Renewable Energy Powered Heterogeneous Cellular Networks

In this paper, maximizing energy efficiency (EE) through radio resource allocation for renewable energy powered heterogeneous cellular networks (HetNet) with energy sharing, is investigated. Our goal is to maximize the network EE, conquer the instability of renewable energy sources and guarantee the fairness of users during allocating resources. We define the objective function as a sum weighted EE of all links in the HetNet. We formulate the resource allocation problem in terms of subcarrier assignment, power allocation and energy sharing, as a mixed combinatorial and non-convex optimization problem. We propose an energy efficient resource allocation scheme, including a centralized resource allocation algorithm for iterative subcarrier allocation and power allocation in which the power allocation problem is solved by analytically solving the Karush-Kuhn-Tucker (KKT) conditions of the problem and a water-filling problem thereafter and a low-complexity distributed resource allocation algorithm based on reinforcement learning (RL). Our numerical results show that both centralized and distributed algorithms converge with a few times of iterations. The numerical results also show that our proposed centralized and distributed resource allocation algorithms outperform the existing reference algorithms in terms of the network EE.     

Interfacial energy between carbon nanotubes and polymers measured from nanoscale peel tests in the atomic force microscope

The future development of polymer composite materials with nanotubes or nanoscale fibers requires the ability to understand and improve the interfacial bonding at the nanotube–polymer matrix interface. In recent work [Strus MC, Zalamea L, Raman A, Pipes RB, Nguyen CV, Stach EA. Peeling force spectroscopy: exposing the adhesive nanomechanics of one-dimensional nanostructures. Nano Lett 2008;8(2):544–50], it has been shown that a new mode in the Atomic Force Microscope (AFM), peeling force spectroscopy, can be used to understand the adhesive mechanics of carbon nanotubes peeled from a surface. In the present work, we demonstrate how AFM peeling force spectroscopy can be used to distinguish between elastic and interfacial components during a nanoscale peel test, thus enabling the direct measurement of interfacial energy between an individual nanotube or nanofiber and a given material surface. The proposed method provides a convenient experimental framework to quickly screen different combinations of polymers and functionalized nanotubes for optimal interfacial strength.     

A new scheme of many-body potentials for hcp metals

A nonspherical symmetric model of embedding atom potential is schemed for hexagonal close-packed (hcp) metals. The empirical embedding energy function and core–core repulsion used in this paper are based on the embedded atom theories of Daw–Baskes (D–B) and Finnis–Sinclair (F–S). The cohesive energy, vacancy formation energy, bulk modulus and elastic constants of five hcp metals are calculated and compared with the experimental data. The results show that it is useful in the calculations of mechanical and cohesive properties of hcp metals and can be used in computer simulations of the study of material properties with molecular dynamic method.     

Magnetically textured ferrofluid in a non-magnetic matrix: Magnetic properties

Texturing of two different magnetic fluids were carried out in paraffin wax under the influence of an external magnetic field. The textured samples were characterized using magnetization measurement and a.c. susceptibility techniques. The results are discussed in the light of ratio of anisotropic energy to magnetic and thermal energies.     

The effect of tip plastic energy on mixed-mode crack initiation

An approach to the fracture initiation prediction of a ductile crack with mixed-mode loading (mode I and II) conditions is presented. The tip plastic energy around the crack tip is applied for evaluating the crack initiation load and the plastic zone shape. It is proposed that a mixed-mode crack will initiate as the tip plastic energy reaches a critical value. Numerical results for various loading conditions are illustrated. These results indicate that the predicted crack initiation loads correlate well with the experimental data available. This revised version was published online in August 2006 with corrections to the Cover Date.     

冰箱的节能与CFCs替代

冰箱耗电量较大，研制节能型冰箱具有重要意义。另外，目前冰箱中使用的制冷剂ＣＦＣ１２不久将被禁用，替代物研究是十分迫切的任务。这也可在研制节能冰箱时与ＣＦＣｓ替代联系起来。本文综述了目前正在研究或已经使用的冰箱节能措施与ＣＦＣ５替代，有利于制订出我国的产品发展方向。     

Misinterpreting the results: How similitude can improve our understanding of fatigue delamination growth

Use of the strain energy release rate for characterizing delamination growth in composite and bonded structures is now commonplace. Analogous to the use of the stress intensity factor range for fatigue crack growth in metals, the strain energy release rate range, defined as the arithmetic difference between maximum and minimum values, is often used to characterize fatigue delamination growth behaviour. The basis for similitude for these two parameters, however, is different and can lead to misinterpretations of delamination growth behaviour if this difference is not understood. This paper examines the basis of similitude for the strain energy release rate range and how it can be redefined in order to avoid potential misinterpretations of fatigue delamination growth.     

An overview—Functional nanomaterials for lithium rechargeable batteries,supercapacitors, hydrogen storage,and fuel cells

There is tremendous worldwide interest in functional nanostructured materials, which are the advanced nanotechnology materials with internal or external dimensions on the order of nanometers. Their extremely small dimensions make these materials unique and promising for clean energy applications such as lithium ion batteries, supercapacitors, hydrogen storage, fuel cells, and other applications. This paper will highlight the development of new approaches to study the relationships between the structure and the physical, chemical, and electrochemical properties of functional nanostructured materials. The Energy Materials Research Programme at the Institute for Superconducting and Electronic Materials, the University of Wollongong, has been focused on the synthesis, characterization, and applications of functional nanomaterials, including nanoparticles, nanotubes, nanowires, nanoporous materials, and nanocomposites. The emphases are placed on advanced nanotechnology, design, and control of the composition, morphology, nanostructure, and functionality of the nanomaterials, and on the subsequent applications of these materials to areas including lithium ion batteries, supercapacitors, hydrogen storage, and fuel cells.