RB-DEM Modeling and Simulation of Non-Persisting Rough Open Joints Based on the IFS-Enhanced Method

When the geological environment of rock masses is disturbed,numerous non-persisting open joints can appear within it.It is crucial to investigate the effect of open joints on the mechanical properties of rock mass.However,it has been challenging to generate realistic open joints in traditional experimental tests and numerical simulations.This paper presents a novel solution to solve the problem.By utilizing the stochastic distribution of joints and an enhanced-fractal interpolation system(IFS)method,rough curves with any orientation can be generated.The Douglas-Peucker algorithm is then applied to simplify these curves by removing unnecessary points while preserving their fundamental shape.Subsequently,open joints are created by connecting points that move to both sides of rough curves based on the aperture distribution.Mesh modeling is performed to construct the final mesh model.Finally,the RB-DEM method is applied to transform the mesh model into a discrete element model containing geometric information about these open joints.Furthermore,this study explores the impacts of rough open joint orientation,aperture,and number on rock fracture mechanics.This method provides a realistic and effective approach for modeling and simulating these non-persisting open joints.

Study on the Exploration of Open Experimental Teaching Methods

Participating in open experimental teaching is essential in cultivating students’innovative ability and comprehensive quality.Participating in open experimental teaching takes students as the main body,which has a substantial effect on improving students’creative power and total quality,at the same time,it enhances the quality of experimental teaching.Based on the existing problems and shortcomings of traditional experiments in private universities,and through the role,methods,and implementation conditions of participating in open experimental education,this article also proposes a four-stage curriculum system of professional basic cognition,practical skills verification,comprehensive design,and technological innovation,to construct a five-in-one open experimental teaching model of“independent experimentteam collaboration-teacher guidance-science and technology competition-industry-university-research cooperation.”Participating in the implementation of open experimental teaching has apparent advantages for students’abilities,the construction of teaching teams,and the development of laboratories.

Preparation of Hadamard Gate for Open Quantum Systems by the Lyapunov Control Method

In this paper, the control laws based on the Lyapunov stability theorem are designed for a two-level open quantum system to prepare the Hadamard gate, which is an important basic gate for the quantum computers. First, the density matrix interested in quantum system is transferred to vector formation.Then, in order to obtain a controller with higher accuracy and faster convergence rate, a Lyapunov function based on the matrix logarithm function is designed. After that, a procedure for the controller design is derived based on the Lyapunov stability theorem. Finally, the numerical simulation experiments for an amplitude damping Markovian open quantum system are performed to prepare the desired quantum gate. The simulation results show that the preparation of Hadamard gate based on the proposed control laws can achieve the fidelity up to 0.9985 for the different coupling strengths.

Strategic information perception methods and practices in the open source intelligence

Open source intelligence is one of the most important public data sources for strategic information analysis. One of the primary and core issues of strategic information research is information perception,so this paper mainly expounds the perception method for strategic information perception in the open source intelligence environment as well as the framework and basic process of information perception. This paper argues that in order to match the information perception result with the information depiction result,it conducts practical exploration for the results of information acquisition,perception,depiction and analysis. This paper introduces and develops a monitoring platform for information perception. The results show that the method proposed in this paper is feasible.

ANALYSIS OF OPEN MICROSTRIP STRUCTURES BY USING DIAKOPTIC METHOD OF LINES COMBINED WITH PERIODIC BOUNDARY CONDITIONS

This paper presents the analysis of open microstrip structures by using diakoptic method of lines (ML) combined with periodic boundary conditions (PBC). The parameters of microstrip patch are obtained from patch current excited by plane wave. Impedance matrix elements are computed by using fast Fourier transform(FFT), and reduced equation is solved by using diakoptic technique. Consequently, the computing time is reduced significantly. The convergence property of simulating open structure by using PBC and the comparison of the computer time between using PBC and usual absorbing boundary condition (ABC) show the validity of the method proposed in this paper. Finally, the resonant frequency of a microstrip patch is computed. The numerical results obtained are in good agreement with those published.

Simulation on venting process and valve opening control method for gas trunk pipelines

Determining the venting time of a gas trunk pipeline segment provides an important basis for formulating an emergency plan in the advent of unexpected accidents.As the natural gas venting process corresponds to the transient flow,it is necessary to establish a transient hydraulic-thermal simulation model in order to determine the venting time.In this paper,based on two kinds of venting scenarios in which there is only one venting point in the venting system of a gas trunk pipeline segment—namely,where the venting point is either at one of the two ends or at the junction of two gas trunk pipeline segments—transient hydraulic-thermal simulation models are established.The models consist of gas flow governing equations,the gas state equation,gas physical property equations,initial conditions,and appropriate boundary conditions.The implicit central difference method is used to discretize the gas flow partial differential equations,and the trust-region-dogleg algorithm is used to solve the equations corresponding to each time step,in order to dynamically simulate the whole venting process.The judgment condition for the end of the venting process is that the average pressure of gas trunk pipeline segment is less than 0.11 MPa(actual pressure).Comparing the simulation results of the proposed model with those of the OLGA software and real operational data,we find that the venting time error is less than 10%.On this basis,a venting valve opening control principle is proposed,which prevents the venting noise from exceeded the specified noise value(85 d B)in the venting design of domestic gas pipeline projects.The established calculation model for venting time(dynamic simulation model)for a gas trunk pipeline segment and the proposed opening control principle of venting valve provide reference for the optimal operation of gas pipeline venting systems.

NUMERICAL MANIFOLD METHOD AND ITS APPLICATION IN UNDERGROUND OPENINGS

A brief introduction is made for the Numerical Manifold Method and its analysing process in rock mechanics. Some aspects of the manifold method are improved in implementing process according to the practice of excavating underground openings. Corresponding formulas are given and a computer program of the Numerical Manifold Method has been completed in this paper.

Linux-based Platform for Open Architecture Controller and Its Modular Developing Method

Linux-based Platform for Open Architecture Controller ( POAC ), a new open architecture controller and its modular developing method are discussed. POAC divides the application software of controller into the developing system and the application system. In the developing system, PAOC abstracts a series of function modules with unified data interface and function interface. In the application system, POAC defines the model of the architecture module, realizing the interoperability and interchangeability between the architecture modules. The modular developing method entities the users to make up an application system with some architecture modules, which consist of a set of function modules. The modular developing method decreases the developing time from the standard of controller architecture to the product.

China Opens Testing Method of Anti-Infective Agents in Cosmetics to Public Consultation

On 14 September, China released a cosmetic testing method standardizing new requirements to test for anti -infective agents in cosmetic products. The draft is for public consultation until 28 Sep, 2018.“Testing Method of Anti-infective Agents in Cosmetics” is used to screen for the presence of 36 kinds of antiinfective agents in cosmetic product types such as liquid water-based, cream, lotion, etc. and determine the quality and quantity by High Performance Liquid Chromatography- Tandem Mass Spectrometry (HPLC-MS/MS).

主动配电网潮流的全纯嵌入计算方法

配电网潮流计算是进行配电网规划和运行的重要基础。目前,配电网潮流求解方法主要有牛拉(Newton Raphson,NR)法和前推回代(forward backward substitution,FBS)法两大类,但NR法和FBS法在潮流收敛性和计算效率等方面均存在一定的不足。全纯嵌入法(holomorphic embedding method,HEM)是一种求解非线性潮流方程的新方法,它可以有效避免NR法和FBS法在配电网潮流求解过程中出现的上述问题,但现有HEM未充分考虑配电网中各类型分布式电源(distributed generation,DG)和智能软开关(soft open point,SOP)控制方式的多样性,且未构建计及负荷电压特性和频率特性的潮流模型,难以适用于不同运行模式下配电网潮流计算。针对上述问题,提出一种可求解含多类型DG和SOP且可运行在并网/孤岛模式的主动配电网统一全纯嵌入潮流计算方法。首先,根据负荷静态电压和频率特性,构建计及配电网频率和节点电压影响的负荷节点全纯嵌入潮流模型;其次,根据DG不同的控制方式以及配电网不同的运行模式,将DG所连节点等效为不同节点类型,构建各类DG的全纯嵌入潮流模型;再次,考虑SOP不同控制方式,构建SOP全纯嵌入潮流模型;从次,依据全纯嵌入潮流模型等式左右两侧同次幂级数系数相等原则,推导配电网各全纯函数幂级数系数的求解递推关系式,进而计算各全纯函数的各项幂级数系数,借助解析延拓理论求取电压和频率逼近值,实现配电网潮流的准确求解;最后,通过修改的IEEE-33节点测试系统和IEEE-123节点测试系统验证所提方法准确性和有效性。

一流课程建设背景下勘探地震学课程教学改革探索与实践

高等教育是支撑、推动和引领国家现代化发展的重要力量,课程建设是高等教育发展的源泉,在以落实立德树人为根本任务,全面开展一流本科课程建设的背景下,开展教育教学改革是优化课程的重要驱动力。勘探地震学课程,从分析传统教学的局限性出发,提出“一引领,三结合,主体性,一体化”的教学改革理念,建设优质丰富的课程资源,实施“四维、六化、全程性评价”的创新改革举措,进行系统的教学模式改革,打造优质课程,培养复合型、高素质、创新性专门人才。该文为相关专业课程进行教学改革提供参考,对进行高质量课程建设具有一定的指导意义。

跨境电商产业政策对出口开放度的影响:来自合成控制法的证据

跨境电商作为数字经济时代的一种贸易新业态,是否有助于缓解当前逆全球化背景下中国外循环面临的挑战值得关注。文章以2012年和2013年实施的跨境贸易电子商务服务试点作为准实验,运用合成控制法进行了反事实分析,以此来识别跨境电商产业政策对试点城市出口开放度的因果效应,并在此基础上进一步从理论和实证的角度揭示了跨境电商产业政策对试点城市出口开放度的影响机制。研究结果表明,跨境电商产业政策显著促进了试点城市的出口开放度,这一结论通过了一系列稳健性检验;机制分析表明,跨境电商产业政策对试点城市出口开放度的影响主要是通过降低试点城市贸易成本这一渠道产生的。基于上述分析,文章最后针对性地提出了相关政策建议。

开放性实验:聚乙烯亚胺修饰碳点的合成、纯化与表征

开放性实验是培养拔尖创新人才的有效手段。我们基于学生兴趣、科研热点和实验室条件,设计了实验方案。实验采用一步水热法,以柠檬酸(CA)为碳源,聚乙烯亚胺(PEI)为修饰剂,合成PEI修饰碳点(PEI-CDs)。首先,将CA、PEI在0.1 mol/L的盐酸中超声至完全溶解,混匀后转移到高压反应釜中,放入烘箱130℃反应2 h,制得PEI-CDs原液;然后将冷却至室温的原液旋转蒸发浓缩至2 mL,并用无水乙醇沉淀、洗涤;最后,将所得沉淀放入真空干燥箱,70℃干燥12 h得到PEI-CDs粉末。利用紫外-可见分光光度计、荧光分光光度计、红外光谱仪和透射电镜对所合成的PEI-CDs进行表征。结果表明,所采用的无水乙醇沉淀纯化方法简单、快速、经济、绿色,制得的PEI-CDs水溶性好,发光性能优异,大小均一,稳定性高。通过该开放性实验,学生不仅熟悉了大型仪器的使用,而且增强了科学研究的兴趣。

基于混合式教学的钢桥课程教学改革探索与实践

钢桥是土木工程专业道桥方向一门与工程实践紧密联系的专业课,教学过程需要引入大量教学案例和实践案例。采用混合式教学模式改革传统教学模式,通过引入线上教学资源,引导学生主动学习、团队学习和探索学习,提升课程教学效率。以武汉理工大学土木工程专业道桥方向钢桥教学为例,阐述钢桥线上教学资源建设、混合教学模式实践与课程改革成效,并介绍持续改进方向。问卷调查显示,学生对钢桥混合式教学模式较为认可;钢桥混合式教学模式实践表明,相比传统单一讲授教学模式,混合式教学模式下学生主动性更强、师生互动良好、课堂效率更高。

开敞空间氢气爆炸特性数值模拟研究

为研究开敞空间氢气爆炸危害,基于Fluent流体力学计算软件建立开敞氢气-空气爆炸的三维数值模型,在此基础上,模拟和分析了边长为0.5、1.0、2.0、3.0 m的立方体预混氢气-空气爆炸,并将数值模拟结果与TNO多能法和BST法的爆炸强度等级进行对比。结果表明,火焰传播距离约为初始氢气半径的2倍。爆炸最大压力出现位置的无量纲距离与气云初始半径近似成线性关系。TNO多能法和BST法爆炸强度等级的选择应根据气云初始尺寸的增大而增加。

档案开放审核问责机制构建的理论阐释、现实梗阻与实践进路

新修订的《中华人民共和国档案法》在档案开放方面提出了更高的要求。作为档案开放的关键环节,档案开放审核面临着巨大挑战。因此,建立健全档案开放审核问责机制十分必要。文章在分析档案开放审核问责机制内涵、作用机理、构建依据的基础上,针对作用机理构建档案开放审核问责机制存在法律法规问责条款有待细化、档案开放审核的问责主体不到位、档案开放审核的问责客体不明确、档案开放审核的问责范围较为狭窄和档案开放审核的问责程序缺乏规范性等困难,提出细化问责政策与条款、全面落实问责主体、切实明确问责客体、调整充实问责范围以及严格规范问责程序等措施,以期为构建档案开放审核问责机制提供参考。

面向光伏能量收集应用的实时MPPT预估算法研究

对于环境中存在的各种类型能量源,其往往具有不同的阻抗特性以及输出功率范围。为了提高能量收集系统的能量萃取能力,合理的接口电路设计是关键。基于此,通过对环境中光伏(Photovoltaic,PV)能量源微弱直流特性以及高效率收集和转化的研究,在传统开路电压法(Open-Circuit Voltage,OCV)的基础上,结合输入电压纹波控制,提出了一种可实时最大功率点追踪(Maximum Power Point Tracking,MPPT)的预估算法。该预估算法根据能量源的输出特性,采用了分数开路电压法(Fractional Open-Circuit Voltage,FOCV),并根据纹波大小动态调节变换器的工作模式,实现阻抗匹配。为了尽可能减小因采样带来的能量损失,采用可片上全集成的较小的采样电容,并逐周期的进行开路电压采样和计算,实现了对源功率变化的高精度追踪。仿真结果表明,所提出的追踪算法能够实时监测能量源的状态,具有高的追踪速度和追踪精度,且采样时间仅需100 ns。能量源功率在1μW~10 mW范围内变化时,最短的追踪时间仅需4.37μs,追踪精度可达99.7%。

基于开口变压器法的交流电机定子非激励相绕组匝间短路检测研究

为了解决交流电机定子绕组中线圈绝缘损伤引起匝间短路故障无法准确、快速定位的问题,提出将检测转子绕组匝间短路的开口变压器法移植到检测交流电机定子绕组匝间短路,定子单相添加激励源,非激励相绕组设置故障点,开口变压器检测故障点所在槽,分析故障前后开口变压器绕组感应电动势的变化。首先阐述开口变压器检测定子非激励相的工作原理,分析正常和故障状态下通过开口变压器铁心漏磁通的表达式,进一步得到开口变压器绕组感应电动势表达式,获取故障变化规律。随后建立交流电机电磁仿真模型,进行仿真分析,最后用一台定子样机进行实验验证。结果表明:故障状态下,随着故障程度的加深,故障点所在槽的开口变压器感应电动势随之减小,证明了开口变压器可以作为离线检测交流电机定子非激励相绕组匝间短路故障的有效手段。

复合式教学法在“遗传学”教学中的应用与实践

“遗传学”是现代生命科学的核心课程,由于学科发展迅速、技术不断进步、知识更新快,传统的授课模式在教学内容、教学方法等方面均存在诸多不足。总结了遗传学教学过程中存在的问题,积极优化教学内容,采用复合式教学法,即启发式、问题式、案例式、科研融入等多种形式针对不同内容选用适合的教学方法,以及科研与教学的有机结合,围绕教材的重点、难点和关键问题,引导学生独立思考。此教学模式充分调动了学生学习遗传学的自主能动性,激发学生的学习兴趣,培养了学生自学、实践和创新能力,提升了学生农业振兴的使命感,取得了良好的教学效果。

以开放性案例为引导的综合设计实验在口腔医学教学中的应用

口腔颌面外科学实验教学是口腔医学临床前教学的重要组成部分,可提高口腔颌面外科学实验课教学质量,培养学生综合能力、创新能力,激发学生学习主动性、积极性。在口腔颌面外科学实验课中根据口腔医学培养目标增设以开放性案例为引导的综合设计实验具有重要意义。以开放性案例为引导的综合设计实验是通过创新实验内容设计,改革教学方法,优化考核方法,融入思政课程达到应用效果。实践证明,该教学模式在一定程度上创新了口腔颌面外科学实验课教学理念,充分调动了学生的学习兴趣,提高了实验教学质量和效率,提高了学生自主学习能力、综合分析能力,构建了有深度、宽度、厚度的教学结构,能为学生后期进入临床学习打好了坚实基础。