Using multivariate adaptive regression splines to develop relationship between rock quality designation and permeability

The assessment of in situ permeability of rock mass is challenging for large-scale projects such as reservoirs created by dams,where water tightness issues are of prime importance.The in situ permeability is strongly related to the frequency and distribution of discontinuities in the rock mass and quantified by rock quality designation(RQD).This paper analyzes the data of hydraulic conductivity and discontinuities sampled at different depths during the borehole investigations in the limestone and sandstone formations for the construction of hydraulic structures in Oman.Cores recovered from boreholes provide RQD data,and in situ Lugeon tests elucidate the permeability.A modern technique of multivariate adaptive regression splines(MARS)assisted in correlating permeability and RQD along with the depth.In situ permeability shows a declining trend with increasing RQD,and the depth of investigation is within 50 m.This type of relationship can be developed based on detailed initial investigations at the site where the hydraulic conductivity of discontinuous rocks is required to be delineated.The relationship can approximate the permeability by only measuring the RQD in later investigations on the same site,thus saving the time and cost of the site investigations.The applicability of the relationship developed in this study to another location requires a lithological similarity of the rock mass that can be verified through preliminary investigation at the site.

A novel approach to structural anisotropy classification for jointed rock masses using theoretical rock quality designation formulation adjusted to joint spacing

Rock quality designation(RQD)has been considered as a one-dimensional jointing degree property since it should be determined by measuring the core lengths obtained from drilling.Anisotropy index of jointing degree(AI_(jd))was formulated by Zheng et al.(2018)by considering maximum and minimum values of RQD for a jointed rock medium in three-dimensional space.In accordance with spacing terminology by ISRM(1981),defining the jointing degree for the rock masses composed of extremely closely spaced joints as well as for the rock masses including widely to extremely widely spaced joints is practically impossible because of the use of 10 cm as a threshold value in the conventional form of RQD.To overcome this limitation,theoretical RQD(TRQD_(t))introduced by Priest and Hudson(1976)can be taken into consideration only when the statistical distribution of discontinuity spacing has a negative exponential distribution.Anisotropy index of the jointing degree was improved using TRQD_(t) which was adjusted to wider joint spacing by considering Priest(1993)’s recommendation on the use of variable threshold value(t)in TRQD_(t) formulation.After applications of the improved anisotropy index of a jointing degree(AI'_(jd))to hypothetical jointed rock mass cases,the effect of persistency of joints on structural anisotropy of rock mass was introduced to the improved AI'_(jd) formulation by considering the ratings of persistency of joints as proposed by Bieniawski(1989)’s rock mass rating(RMR)classification.Two real cases were assessed in the stratified marl and the columnar basalt using the weighted anisotropy index of jointing degree(W_AI'_(jd)).A structural anisotropy classification was developed using the RQD classification proposed by Deere(1963).The proposed methodology is capable of defining the structural anisotropy of a rock mass including joint pattern from extremely closely to extremely widely spaced joints.

Suggestions on Improving China’s Breakthrough Therapy Designation System

Objective To analyze the characteristics of breakthrough therapy designation(BTD)and its implementation in China,and to provide reference for the optimization of BTD system.Methods A comparative research method was used to study the content and implementation effect of BTD system in China and the relevant policies and implementation of the same procedures of drug regulatory authorities in the United States,Japan and the European Union.Then,the differences in policies and implementation results among these countries were analyzed to provide suggestions for the implementation and optimization of this system in China.Results and Conclusion China’s BTD system is implemented late and a small number of drugs has been approved.At the same time,there are problems such as insufficient guidance and communication from the agency to applicants,a broad application condition,single review mode,and lack of full-time personnel.Both the agencies and the applicants have limited experience due to the short implementation time of BTD system in China.There are still some problems despite we have learned a lot from the experience of other drug regulatory agencies.Therefore,based on our national conditions,we should strengthen the guidance of evaluation agency to applicants,optimize the eligibility criteria of BTD system,introduce the rolling review,and increase the number of professional liaisons,which can accelerate the development and marketing process of drugs with obvious clinical value,and finally to address unmet medical need.

A Review:From Aquatic Lives Locomotion to Bio-inspired Robot Mechanical Designations

With the development of camera technology,high-speed cameras have greatly contributed to capturing the movement and posture of animals,which has dramatically promoted experimental biology research.At the same time,with the concept of bionics gradually gaining popularity among researchers,the design of robots is absorbing more and more biological features,where the interest in the bio-inspired robot is hewed out.Compared with the traditional robot,the bio-inspired robot imitates the motion pattern to achieve similar propulsion features,which may be more effective and reasonable.In this paper,the motion patterns of aquatic animals are divided into four categories according to their propulsion mechanisms:drag-based,lift-based,jet-based,and interface-based.And bio-inspired robots imitating aquatic prototypes are introduced and reviewed.Finally,the prospect of aquatic bio-inspired robots is discussed.

水田动力底盘逆向建模与质心验证——基于Geomagic Design X

针对目前农业机械仿真和优化模型精度不高的问题,提出了一种构建精确模型的逆向建模方法。应用光学扫描仪采集点云数据,基于Geomagic Design X处理点云数据并重构零部件模型,在SolidWorks中完成水田动力底盘的装配。以VP6D-CQ型水田动力底盘为例,将测得的实际质心位置与所建的模型质心位置进行比较,并对提出的逆向建模方法进行了试验验证以及误差分析。结果表明:总质量、x坐标、y坐标、z坐标的误差值分别为4.55%、3.62%、2.23%、4.81%,误差值均在5%内。此方法可构建准确的三维模型,为后续仿真优化数据精确性奠定了基础,与传统的研发相比较,可缩短农业机械研发周期、降低设计成本。

车载信息交互系统复杂性设计管理发展研究

目的梳理车载信息交互系统及其复杂性管理的发展脉络,并提出多元设计策略以指导车载信息交互系统设计。方法首先利用Vosviewer进行文献检索,梳理出目前车载信息交互领域的研究热点;然后通过文献回顾的方式总结传统车载信息交互系统的复杂性演变;最后利用Design X的设计策略,从用户、系统、信息等角度,分析数智时代下的车载信息交互系统存在的任务复杂性及交互复杂性。结论基于Design X的设计策略,从用户群体分析、车载信息优化、智慧交通系统搭建等角度,提出有关管理车载信息交互系统复杂性的多元设计策略,为后续车载信息交互设计提供参考。

基于MATLAB的射频微波电路阻抗匹配教学软件设计

阻抗匹配是射频微波电路设计的重要内容,然而阻抗匹配方案众多且计算繁杂,原有教学大多以中心频率匹配的数学公式推导为主,学生难以理解不同匹配方案在较宽频带内的整体性能表现。为此,基于MATLAB App Designer开发了一款阻抗匹配设计和分析软件,可实现包含集总参数电感电容和分布参数微带线在内的多种宽带、窄带匹配方案,通过输入技术指标要求便可直接得到对应的电路结构、元件值以及S参数曲线。该软件操作简单、实时性强,可快速比较多种匹配方案的性能,加强学生对阻抗匹配的深层次理解,极大地辅助了教学和科研。

用于化学品数据查询和TNT当量计算软件的研究与实现

本文介绍了一款基于Matlab App designer的化学品查询、WTNT、NTNT计算和数据保存的软件——化学品数据查询和TNT当量计算软件。该软件能够通过CAS检索服务号查询化学品相关信息,包括闪点、爆炸极限、自燃点、火灾危险性分类,并计算WTNT和NTNT,同时还支持数据保存功能。阐述了系统的功能模块和开发过程,介绍了系统的操作方法和使用效果,为化学品数据查询和TNT当量计算提供了一种简便、快捷的方法。

《电力电子技术》课程教学改革研究

在工程教育背景下,为增强课堂教学实效,以产出为导向,培养学生工程应用能力,对电气工程及其自动化专业的核心课程《电力电子技术》进行改革。分析了课程教学中存在的问题,如实践能力培养欠缺、实验教学效果差、教学方法单一、课程考核综合性不强和课程思政缺乏等;提出了改进方法,如引入MATLAB仿真、加强信息化教学、运用Altium Designer进行电路实物制作、改进教学方法、多环节考核和融入课程思政等,实践证明了其可行性和有效性。

Recent Progress in Reinforcement Learning and Adaptive Dynamic Programming for Advanced Control Applications

Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and its applications to various advanced control fields. First, the background of the development of ADP is described, emphasizing the significance of regulation and tracking control problems. Some effective offline and online algorithms for ADP/adaptive critic control are displayed, where the main results towards discrete-time systems and continuous-time systems are surveyed, respectively.Then, the research progress on adaptive critic control based on the event-triggered framework and under uncertain environment is discussed, respectively, where event-based design, robust stabilization, and game design are reviewed. Moreover, the extensions of ADP for addressing control problems under complex environment attract enormous attention. The ADP architecture is revisited under the perspective of data-driven and RL frameworks,showing how they promote ADP formulation significantly.Finally, several typical control applications with respect to RL and ADP are summarized, particularly in the fields of wastewater treatment processes and power systems, followed by some general prospects for future research. Overall, the comprehensive survey on ADP and RL for advanced control applications has d emonstrated its remarkable potential within the artificial intelligence era. In addition, it also plays a vital role in promoting environmental protection and industrial intelligence.

Engineering Strategies for Suppressing the Shuttle Effect in Lithium–Sulfur Batteries

Lithium–sulfur(Li–S)batteries are supposed to be one of the most potential next-generation batteries owing to their high theoretical capacity and low cost.Nevertheless,the shuttle effect of firm multi-step two-electron reaction between sulfur and lithium in liquid electrolyte makes the capacity much smaller than the theoretical value.Many methods were proposed for inhibiting the shuttle effect of polysulfide,improving corresponding redox kinetics and enhancing the integral performance of Li–S batteries.Here,we will comprehensively and systematically summarize the strategies for inhibiting the shuttle effect from all components of Li–S batteries.First,the electrochemical principles/mechanism and origin of the shuttle effect are described in detail.Moreover,the efficient strategies,including boosting the sulfur conversion rate of sulfur,confining sulfur or lithium polysulfides(LPS)within cathode host,confining LPS in the shield layer,and preventing LPS from contacting the anode,will be discussed to suppress the shuttle effect.Then,recent advances in inhibition of shuttle effect in cathode,electrolyte,separator,and anode with the aforementioned strategies have been summarized to direct the further design of efficient materials for Li–S batteries.Finally,we present prospects for inhibition of the LPS shuttle and potential development directions in Li–S batteries.

Relationship between the unique microstructures and behaviors of high-entropy alloys

High-entropy alloys(HEAs),which were introduced as a pioneering concept in 2004,have captured the keen interest of nu-merous researchers.Entropy,in this context,can be perceived as representing disorder and randomness.By contrast,elemental composi-tions within alloy systems occupy specific structural sites in space,a concept referred to as structure.In accordance with Shannon entropy,structure is analogous to information.Generally,the arrangement of atoms within a material,termed its structure,plays a pivotal role in dictating its properties.In addition to expanding the array of options for alloy composites,HEAs afford ample opportunities for diverse structural designs.The profound influence of distinct structural features on the exceptional behaviors of alloys is underscored by numer-ous examples.These features include remarkably high fracture strength with excellent ductility,antiballistic capability,exceptional radi-ation resistance,and corrosion resistance.In this paper,we delve into various unique material structures and properties while elucidating the intricate relationship between structure and performance.

Recent advances in cobalt phosphide-based materials for electrocatalytic water splitting:From catalytic mechanism and synthesis method to optimization design

Electrochemical water splitting has long been considered an effective energy conversion technology for trans-ferring intermittent renewable electricity into hydrogen fuel,and the exploration of cost-effective and high-performance electrocatalysts is crucial in making electrolyzed water technology commercially viable.Cobalt phosphide(Co-P)has emerged as a catalyst of high potential owing to its high catalytic activity and durability in water splitting.This paper systematically reviews the latest advances in the development of Co-P-based materials for use in water splitting.The essential effects of P in enhancing the catalytic performance of the hydrogen evolution reaction and oxygen evolution reaction are first outlined.Then,versatile synthesis techniques for Co-P electrocatalysts are summarized,followed by advanced strategies to enhance the electrocatalytic performance of Co-P materials,including heteroatom doping,composite construction,integration with well-conductive sub-strates,and structure control from the viewpoint of experiment.Along with these optimization strategies,the understanding of the inherent mechanism of enhanced catalytic performance is also discussed.Finally,some existing challenges in the development of highly active and stable Co-P-based materials are clarified,and pro-spective directions for prompting the wide commercialization of water electrolysis technology are proposed.

Analysis of the interaction between bolt-reinforced rock and surface support in tunnels based on convergence-confinement method

To investigate the interaction of the bolt-reinforced rock and the surface support,an analytical model of the convergence-confinement type is proposed,considering the sequential installation of the fully grouted rockbolts and the surface support.The rock mass is assumed to be elastic-brittle-plastic material,obeying the linear Mohr-Coulomb criterion or the non-linear Hoek-Brown criterion.According to the strain states of the tunnel wall at bolt and surface support installation and the relative magnitude between the bolt length and the plastic depth during the whole process,six cases are categorized upon solving the problem.Each case is divided into three stages due to the different effects of the active rockbolts and the passive surface support.The fictitious pressure is introduced to quantify the threedimensional(3D)effect of the tunnel face,and thus,the actual physical location along the tunnel axis of the analytical section can be considered.By using the bolt-rock strain compatibility and the rocksurface support displacement compatibility conditions,the solutions of longitudinal tunnel displacement and the reaction pressure of surface support along the tunnel axis are obtained.The proposed analytical solutions are validated by a series of 3D numerical simulations.Extensive parametric studies are conducted to examine the effect of the typical parameters of rockbolts and surface support on the tunnel displacement and the reaction pressure of the surface support under different rock conditions.The results show that the rockbolts are more effective in controlling the tunnel displacement than the surface support,which should be installed as soon as possible with a suitable length.For tunnels excavated in weak rocks or with restricted displacement control requirements,the surface support should also be installed or closed timely with a certain stiffness.The proposed method provides a convenient alternative approach for the optimization of rockbolts and surface support at the preliminary stage of tunnel design.

电驱动矿用自卸车轮毂驱动系统动态疲劳可靠性分析

针对在设计阶段无法准确评估实际载荷下轮毂驱动系统可靠性的问题,提出了一种适用于设计阶段的轮毂驱动系统可靠性评估方法。以额定设计静载荷代替实际随机载荷,计算了轮毂驱动系统各个齿轮副动态疲劳可靠性。并通过Romax Design软件模拟试验了实际载荷下的轮毂驱动系统各个齿轮副的疲劳损伤与可靠性,验证了此方法的可行性,为轮毂驱动系统的可靠性设计提供了理论依据和实际试验指导。

驱动电机轴承热特性分析系统设计与验证

针对新能源汽车驱动电机轴承热特性分析过程中,其温升及接触分析计算过于复杂、计算效率低的问题,采用MATLAB App Designer软件开发工具,在建立驱动电机轴承温升及接触分析模型和编制其数值求解程序的基础上,设计一套新能源汽车驱动电机轴承热特性分析系统。该系统使用方便,只需输入轴承的相关参数,便可直接计算出轴承相应的温升、发热功耗和接触载荷等性能参数,且计算结果可在系统界面以图表的形式进行显示和输出。与试验数据的对比结果表明,该系统高效可靠,为工程设计中其他复杂计算系统的开发提供了参考。

发动机叶轮的逆向建模与3D打印研究

为了高效地生产出高精度的叶轮,采用激光扫描仪对发动机叶轮原件进行扫描,对点云数据进行处理,利用逆向建模软件Geomagic Design X对其进行模型重构,将重构的数据与原件相比较,并进行3D打印,最终得出逆向建模能够获取较高精度的叶轮模型,3D打印能够快速高效地打印叶轮模型,从而为解决叶轮加工难度大、工序复杂等问题提供了一种新方法,也为缩短产品生产周期提供了便捷。

Designation and Development of Central Towns: A Case Study of Shiyan

In China, central towns are an important pitch point in the urban system of a city or county. The cultivation and development of central towns is significant in completing the urban system structure and improving the overall quality of urban-rural development of a city or county. In the Municipality of Shiyan, a mountainous region in Hubei Province, the designation of central towns should not be mechanically accomplished through applying the methodology used in plain areas, but with particular focus on the location and transportation of the towns. Based on the analysis of comprehensive development potential, 14 central towns are finally designated in Shiyan in view of their favorable location and the requirement of coordinated regional development. Development strategies are also proposed for them which include the improvement of urban functions, the differentiation of development modes, the growth of industrial clusters, the development of environmental-friendly industries, the standard configuration of public service facilities, and the institutional reform and innovation which would ensure the realization of the central towns' function of agglomeration and radiation.

基于“Design Thinking”理念的职业院校创新创业人才培养模式

随着我国经济不断发展和社会进步,创新创业已经成为推动经济增长的关键驱动力,在2015年全国人民代表大会上,李克强总理将“大众创业、万众创新”明确列为我国经济增长的“双引擎”之一,彰显了创新创业对于推动社会发展的重要地位。为响应国家政策,各高校积极开展创新创业教育,将其纳入高等教育综合改革的重要议程,成为培养未来人才的重要途径。本文分析了“Design Thinking”理念下职业院校创新创业人才培养的必要性,围绕新时期专业院校创新创业人才培养的要求,提出了基于“Design Thinking”理念的职业院校创新创业人才培养模式的有效策略,为职业院校人才培养效率的强化提供了参考性意见。

基于MVVM模式SpringBoot框架的高校信息化项目管理系统

传统的Java EE应用以Spring MVC、Mybatis、FreeMarker为核心,具有架构分层不清晰、前后端代码耦合性高、不易扩展等缺点。为提高轻量级Java EE应用的开发效率,提出一种基于Ant Design、React、SpringBoot、Apache Cayenne框架的Java EE应用架构。其基于MVVM模式,以SpringBoot为核心向上集成Ant Design和React为前端,向下集成Apache Cayenne为后端,集成后的架构通过Ant Design和React实现表示层,通过SpringBoot实现控制层和业务逻辑层,通过Apache Cayenne实现数据持久层。基于此开发的高校信息化项目管理系统,架构层次清晰,前后端代码彻底分离,可供高校信息化项目管理部门使用和推广。