Macroscopic and microscopic mechanical behavior and seepage characteristics of coal under hydro-mechanical coupling

Understanding the physical,mechanical behavior,and seepage characteristics of coal under hydro-mechanical coupling holds significant importance for ensuring the stability of surrounding rock formations and preventing gas outbursts.Scanning electron microscopy,uniaxial tests,and triaxial tests were conducted to comprehensively analyze the macroscopic and microscopic physical and mechanical characteristics of coal under different soaking times.Moreover,by restoring the stress path and water injection conditions of the protective layer indoors,we explored the coal mining dynamic behavior and the evolution of permeability.The results show that water causes the micro-surface of coal to peel off and cracks to expand and develop.With the increase of soaking time,the uniaxial and triaxial strengths were gradually decreased with nonlinear trend,and decreased by 63.31%and 30.95%after soaking for 240 h,respectively.Under different water injection pressure conditions,coal permeability undergoes three stages during the mining loading process and ultimately increases to higher values.The peak stress of coal,the deviatoric stress and strain at the permeability surge point all decrease with increasing water injection pressure.The results of this research can help improve the understanding of the coal mechanical properties and seepage evolution law under hydro-mechanical coupling.

基于PMAC的MACROStation的应用

介绍了PMAC运动控制器及MACROStation(宏运动控制站)的概念。阐述MACROStation的设置及映射的建立,结合轧辊磨床专用数控系统的建立,介绍MACROStation的应用及其实际意义。

Damage detection of a thin plate using modal curvature via macrostrain measurement

Plate structures are employed as important structural components in many engineering applications. Hence, assessing the structural conditions of in-service plate structures is critical to monitoring global structural health. Modal curvature-based damage detection techniques have recently garnered considerable attention from the research community, and have become a promising vibration-based structural health monitoring solution. However, computing errors arise when calculating modal curvatures from lateral mode shapes, which result from unavoidable measurement errors in the mode shapes as identified from lateral vibration signals; this makes curvature-based algorithms that use a lateral measurement only theoretically feasible, but practically infeasible. Therefore, in this study, long-gauge fiber Bragg grating strain sensors are employed to obtain a modal curvature without a numerical differentiation procedure in order to circumvent the computing errors. Several damage indices based on modal curvatures that were developed to locate beam damage are employed. Both numerical and experimental studies are performed to validate the proposed approach. However, although previous studies have reported relative success with the application of these damage indices on a simple beam, only one damage index demonstrated the capability to locate damage when the stiffness of the local region changed near the sensor.

Multi-type ant system algorithm for the time dependent vehicle routing problem with time windows

The time dependent vehicle routing problem with time windows（TDVRPTW） is considered. A multi-type ant system（MTAS） algorithm hybridized with the ant colony system（ACS）and the max-min ant system（MMAS） algorithms is proposed. This combination absorbs the merits of the two algorithms in solutions construction and optimization separately. In order to improve the efficiency of the insertion procedure, a nearest neighbor selection（NNS） mechanism, an insertion local search procedure and a local optimization procedure are specified in detail. And in order to find a balance between good scouting performance and fast convergence rate, an adaptive pheromone updating strategy is proposed in the MTAS. Computational results confirm the MTAS algorithm＇s good performance with all these strategies on classic vehicle routing problem with time windows（VRPTW） benchmark instances and the TDVRPTW instances, and some better results especially for the number of vehicles and travel times of the best solutions are obtained in comparison with the previous research.

Multi-type sensor placement and response reconstruction for building structures: Experimental investigations

Estimation of lateral displacement and acceleration responses is essential to assess safety and serviceability of high-rise buildings under dynamic loadings including earthquake excitations. However, the measurement information from the limited number of sensors installed in a building structure is often insufficient for the complete structural performance assessment. An integrated multi-type sensor placement and response reconstruction method has thus been proposed by the authors to tackle this problem. To validate the feasibility and effectiveness of the proposed method, an experimental investigation using a cantilever beam with multi-type sensors is performed and reported in this paper. The experimental setup is first introduced. The finite element modelling and model updating of the cantilever beam are then performed. The optimal sensor placement for the best response reconstruction is determined by the proposed method based on the updated FE model of the beam. After the sensors are installed on the physical cantilever beam, a number of experiments are carried out. The responses at key locations are reconstructed and compared with the measured ones. The reconstructed responses achieve a good match with the measured ones, manifesting the feasibility and effectiveness of the proposed method. Besides, the proposed method is also examined for the cases of different excitations and unknown excitation, and the results prove the proposed method to be robust and effective. The superiority of the optimized sensor placement scheme is finally demonstrated through comparison with two other different sensor placement schemes： the accelerometer-only scheme and non-optimal sensor placement scheme. The proposed method can be applied to high-rise buildings for seismic performance assessment.

Understanding the superior mechanical properties of Mg-3Al-Zn alloy sheets:Role of multi-type unique textures

Mg-3Al-1Zn(AZ31)sheets were produced by transverse gradient extrusion(TGE)process.The flow behavior and dynamic recrystallization during extrusion were systematically analyzed.The microstructures,textures,and mechanical behavior of extruded AZ31 sheet were also analyzed and compared with conventional extruded(CE)sheet.The results showed that fine grain structure and multi-type unique textures were formed in TGE sheet because of the generation of extra flow velocity along transverse direction(TD)and flow velocity gradient along extrusion direction(ED)during extrusion.The basal poles gradually deviated away normal direction(ND)from edge to center of the TGE sheet along TD,and the largest inclination angle at center region reached around 65°.Furthermore,the basal poles inclined from ED to TD 40°-63°,except for the center region of TGE sheet.The TGE sheet presented higher ductility and strain hardening exponent(n-value),but lower yield strength and Lankford value(r-value)in comparison with the CE sheet.Both the basal<a>slip and tensile twins were easy to be activated during deformation,and the largest elongation of 41%and the lowest yield strength of 86.5 MPa were obtained for the ED-center sample in the TGE sheet.

Inferring Multi-Type Birth-Death Parameters for a Structured Host Population with Application to HIV Epidemic in Africa

Human Immunodeficiency Virus (HIV) dynamics in Africa are purely characterised by sparse sampling of DNA sequences for individuals who are infected. There are some sub-groups that are more at risk than the general population. These sub-groups have higher infectivity rates. We came up with a likelihood inference model of multi-type birth-death process that can be used to make inference for HIV epidemic in an African setting. We employ a likelihood inference that incorporates a probability of removal from infectious pool in the model. We have simulated trees and made parameter inference on the simulated trees as well as investigating whether the model distinguishes between heterogeneous and homogeneous dynamics. The model makes fairly good parameter inference. It distinguishes between heterogeneous and homogeneous dynamics well. Parameter estimation was also performed under sparse sampling scenario. We investigated whether trees obtained from a structured population are more balanced than those from a non-structured host population using tree statistics that measure tree balance and imbalance. Trees from non-structured population were more balanced basing on Colless and Sackin indices.

Study on the Effect of Multi-Type Current Transformers Hybrid Operation on Differential Protection of the Bus Based on Dynamic Simulation

This paper analyzes characteristics of multi type current transformers hybrid operation for each branch of the bus and their effects on differential protection of the bus. By theoretically analyzing transmission characteristics of multi type current transformers and their influence factors, we study the dynamic model testing method of multi type current transformers for the bus, and design 3 kinds of testing schemes by making the equivalent model based on the field of P-level current transformer, TPY-level current transformer and electronic current transformer, and build the hybrid operation testing platform of multi type current transformers. Finally, we compare and analyze the transmission characteristics difference of multi type current transformers on the same branch and the characteristics difference of hybrid operation in two successive external faults, analyze the cause behind the differences, and put forward the corresponding improvement measures.

VAX—11宏汇编I／O库MACROS

本文给出了一种解决VAX机汇编程序设计中输入／输出问题的宏汇编I／O库－MACROS库，并对该库的功能，设计原理及方法、库的产生与使用规则等方面作了详细的介绍，最后举例说明了使用的步骤以及编写该库的源程序清单。

iOpus Internet Macros 重复工作我不怕

如果你是一名网虫，那么肯定知道网络中有很多事情都是完全重复的，例如每天需要访问相同的站点、使用搜索引擎、查看新闻、收取邮件、记录密码，测试网站等。iOpus公司的Internet Macros就是一个专门为微软IE浏览器和网络设计的宏录制工具。一旦你录制好了宏，只需要点击一下鼠标就可以重复设定的工作。

基于MACRO总线的开放式凸轮轴磨床数控系统

本文主要讨论基于MACRO总线的开放式凸轮轴磨床数控系统的硬件、软件结构及基于恒线速插补算法的实现。该系统采用高速DSP作为伺服控制核心 ,通过MACRO高速光纤网将工业PC和下位控制系统联接。在工业PC上采用保证恒线速的磨削点搜索算法离线完成从凸轮升程或型线参数到每个插补点的计算工作 ,再将插补结果进行样条拟合 ,输入到基于DSP的下位控制系统 ,控制系统根据样条曲线控制砂轮进给和工件主轴的协调运动 。

EXPERIMENTAL STUDY ON THE MACRO-AND MICRO- CHARACTERISTICS OF THE SPRAY FROM A PRESSURE SWIRL NOZZLE

The experimental study on the macro and micro characteristics of the spray from a pressure swirl nozzle embraces the growth of surface unstable wave,disintegration process,spray angle,breakup length and so on.The effects of injection pressure,nozzle geometry and liquid properties on these characteristics are also discussed.The results are helpful to understand the underlying physics of the pressure swirl nozzle and serve as the basis for the practical design,usage and improvement of the nozzle.

MACRO协议及在开放式数控中的应用

MACRO(MotionandControlRingOptical)是美国DeltaTau公司为运动控制系统开发的以光纤或双绞线为介质的高速通讯协议，具有速度高、可靠性好、对用户透明等优点，并得到了世界上多家伺服、PLC及其它自动化产品制造商的支持。本文主要介绍MACRO通讯协议及其在3维激光加工设备中的应用。

基于XML/Macro的文档自动生成系统的研究与实现

提出了支持作战仿真系统的一种新的基于XML/Macro的文档自动生成系统的体系结构,开发了文档自动生成系统,实现了复合文档的自动生成。

基于PMAC的MACRO station的应用及设置

简单介绍PMAC运动控制器及MACRO station(宏运动控制站)后,结合轧辊磨床专用数控系统的建立,介绍MACRO station的应用。阐述PMAC和MACRO station中各个模块间的内在关系,以及它们和外部设备间的关系;PMAC中相关I变量的设置方法;各种映射关系的建立,以及MACRO STATION的应用实际意义。

VAX MACRO程序设计中的I／O问题

ＶＡＸＭＡＣＲＯ语言不包括任何Ｉ／Ｏ成分。一个完善的Ｉ／Ｏ工具对于ＭＡＣＲＯ程序员至关重要。在现有的书中尚未发现令人满意的Ｉ／Ｏ工具。笔者开发的宏ｒｅａｄ和ｗｒｉｔｅ，既简单又有效。本文将介绍它们的用法和实现技术。

元素分析仪(Elementar Vario MACRO)测定石灰性土壤C、N时存在问题的探讨

壤全氮、土壤有机质的测定对农业生产和科学研究都有重要意义。因此在许多实验室里,土壤全氮、土壤有机质都被作为一项常规分析项目。土壤全氮量的测定百余年来沿用杜马氏法和凯氏定氮法。测定土壤有机质的方法主要有3种:干烧法、化学氧化法、灼烧法,1989年农业部颁布了国标GB9843-88《土壤有机质测定法》。近年来使用元素分析仪(Elementar Vario MACRO)测定土壤C、N也越来越广泛,元素分析仪是一台用于快速,定量测定元素C、H、N、S的全自动分析仪。用元素分析仪测定C、H、N的方法属于灼烧法,灼烧温度为960摄氏度,对酸性、中性土壤的测定无疑是省时准确的首选。石灰性土壤中由于碳酸盐的存在,在高温灼烧时碳酸盐分解,形成CO2,使土壤有机质的测定结果偏高。降低燃烧管温度测定(630摄氏度),由于样品用锡箔纸包裹,锡箔纸在燃烧管内燃烧生成氧化锡为放热反应,增加燃烧管内的温度高于设定温度,增加碳酸钙的分解测定值偏高,燃烧管温度设定在低于碳酸盐分解点时仪器密封不严实,使测定结果偏低。用盐酸处理土壤中碳酸盐,其后测定有机质时,因土壤中的富里酸溶于酸,使测定结果偏低。因此元素分析仪不适于石灰性土壤有机质的测定。

实测上海移动4G建设样板点Easy Macro和CA让4G更快更好

在4G网络建设中,上海移动结合利用Easy Macro、Lamp Site、Atom、Relay、AAU3213等华为创新方案,灵活解决了多种场景下的覆盖问题。

FORTRAN与MACRO之间的最佳数据交换

一、数据交换环境随着计算机应用领域的不断扩大,同一计算机上运行的不同程序设计语言程序之间进行数据交换已引起越来越多的注意和讨论.文[1]讨论了在VAX—11/750计算机上运行的一个实时数据采集处理系统(DAS)