A comparative study on kinetics and dynamics of two dump truck lifting mechanisms using MATLAB simscape

In this paper,two lifting mechanism models with opposing placements,which use the same hydraulic hoist model and have the same angle of 50°,have been developed.The mechanical and hydraulic simulation models are established using MATLAB Simscape to analyze their kinetics and dynamics in the lifting and holding stages.The simulation findings are compared to the analytical calculation results in the steady state,and both methods show good agreement.In the early lifting stage,Model 1 produces greater force and discharges goods in the container faster than Model 2.Meanwhile,Model 2 reaches a higher force and ejects goods from the container cleaner than its counterpart at the end lifting stage.The established simulation models can consider the effects of dynamic loads due to inertial moments and forces generated during the system operation.It is crucial in studying,designing,and optimizing the structure of hydraulic-mechanical systems.

Research on the Lifting Path of Data Literacy Ability of Applied University Teachers under the Perspective of Organizational Learning

With the arrival of the big data era, the modern higher education model has undergone radical changes, and higher requirements have been put forward for the data literacy of college teachers. The paper first analyzes the connotation of teacher data literacy, and then combs through the status quo and dilemmas of teachers’ data literacy ability in applied universities. The paper proposes to enhance the data literacy ability of teachers from the perspective of organizational learning. Through building a digital culture, building a data-driven teaching environment, and constructing an interdisciplinary learning community to further promote the application of the theory and practice of datafication inside and outside the organization, and ultimately improve the quality of teaching.

Dynamic Analysis of Pipeline Lifting Operations for Different Current Velocities and Wave Heights

Pipelines are widely used for transporting oil resources in the context of offshore oil exploitation.The pipeline stress-strength analysis is an important stage in related design and ensuing construction techniques.In this study,assuming representative work environment parameters,pipeline lifting operations are investigated numerically.More specifically,a time-domain coupled dynamic analysis method is used to conduct a hydrodynamic analysis under different current velocities and wave heights.The results show that proper operation requires the lifting points are reasonably set in combination with the length of the pipeline and the position of the lifting device on the construction ship.The impact of waves on the pipeline is limited,however lifting operations under strong wind and waves should be avoided as far as possible.

Bionic microchannels for step lifting transpiration

Those various cross-sectional vessels in trees transfer water to as high as 100 meters,but the traditional fabrication methods limit the manufacturing of those vessels,resulting in the non-availability of those bionic microchannels.Herein,we fabricate those bionic microchannels with various cross-sections by employing projection micro-stereolithography(PμSL)based 3D printing technique.The circumradius of bionic microchannels(pentagonal,square,triangle,and five-pointed star)can be as small as 100μm with precisely fabricated sharp corners.What's more,those bionic microchannels demonstrate marvelous microfluidic performance with strong precursor effects enabled by their sharp corners.Most significantly,those special properties of our bionic microchannels enable them outstanding step lifting performance to transport water to tens of millimeters,though the water can only be transported to at most 20 mm for a single bionic microchannel.The mimicked transpiration based on the step lifting of water from bionic microchannels is also achieved.Those precisely fabricated,low-cost,various cross-sectional bionic microchannels promise applications as microfluidic chips,long-distance unpowered water transportation,step lifting,mimicked transpiration,and so on.

一种生成双正交紧支复小波的Lifting方法

提出了一种构造双正交紧支复小波的方法 :以现有任何一种正交或双正交实小波为基础 ,可构造出消失矩阶数可任意选定的无穷多个相频特性 (包括线性相位特性 )不同的双正交紧支复小波。其特点为 :由于是双正交紧支型 ,可采用Mallat算法等快速算法 ,因此使用时实时性好 ;因为是复小波 ,所以能提取电力系统至关重要的相位信息 ;具有多种相频特性 ,便于与相频特性多变的电力系统信号匹配等 ,因此这类小波在电力系统有广泛的应用前景。

Lifting Scheme及其在小波图象编码中的应用

L ifting Schem e是构造第二代小波的关键技术 .相对于第一代小波而言 ,L ifting Scheme是一种比 Mallat算法更快、更简单和更容易操作的算法 ,也是 JPEG2 0 0 0推荐的算法 .为了将其应用到小波图象编码中 ,提出了一种对 L ifting Scheme作适当改进以用于小波图象编码的方法 .该方法就是先用 L ifting Scheme来实现 D9/ 7双正交小波变换 ,然后再用这种技术实现的 D9/ 7双正交小波变换来进行图象压缩编码 .在将 L ifting Schem e算法用于小波图象编码的过程中 ,对该算法做了必要的简化 ,以便保证每个提升 (lifting)环节都是 FIR滤波 .同时 ,根据能量守恒的原则 ,重新调整了尺度因子 .实验结果表明 ,这种经过改进的 L ifting Schem e取得了比

细分曲面切片轮廓线的Lifting小波变换

基于Lifting小波变换原理对细分曲面实体切片操作产生的离散交点序列进行处理,将它们组织为属于多个层次结构的多分辨率曲线。用4种不同的Lifting小波变换进行了多分辨率曲线的构造实验,并对产生的多分辨率曲线进行了对比,讨论分析了这些Lifting变换方法的性能特点。

利用lifting方法设计双正交滤波器组

研究了用lifting方法设计三通道自适应提升双正交滤波器组.在设计中,用子带编码增益作为设计准则,从任意一个滤波器组(标准正交或双正交)开始,通过联合自适应提升方法来设计三通道双正交滤波器组.最后,给出例子说明子带码增益明显提高.

关联规则分析中兴趣度量Lift与Conviction的关系探讨及教育数据验证

关联规则分析是数据挖掘中最常用的研究方法之一。在关联关系的发现过程中兴趣度量是关联规则发现的理论基础,它可以度量规则的重要程度,其中Lift和Conviction这两个度量在数据分析中被广泛应用于筛选关联规则。本文对这两种兴趣度量进行了研究。首先,提出并证明了当后项集固定时,Conviction取值随Lift取值单调增加,且Conviction (Lift)是一个凸函数。然后,证明了当Confidence固定时,Conviction取值随Lift取值单调增加,且Conviction (Lift)是一个凹函数。最后,综合以上两个方面,得到一个重要结论:当后项集保持不变或当Confidence固定时,根据Conviction和Lift筛选出来的规则都是相同的。最后,利用某高校数学类专业三个年级的成绩数据进行了定理及相应结论的验证。

浮动基多机协调吊运系统的工作空间分析

At present,the cranes used at sea have several shortcomings in terms of flexibility,efficiency,and safety.Therefore,a floating multi-robot coordinated lifting system is proposed to fulfill the offshore lifting requirements.First,the structure of the lifting system is established according to the lifting task,the kinematic model of the system is developed by using the D–H coordinate transformation,and the dynamic model is developed based on rigid-body dynamics and hydrodynamics.Then,the static and dynamic workspace of the lifting system are analyzed,and the solving steps of the workspace are given by using the Monte–Carlo method.The effect of the load mass and the maximum allowable tension of the cable on the workspace is examined by simulation.Results show that the lifting system has limited carrying capacity and a data reference for selecting the structural parameters by analyzing the factors affecting the workspace.Findings provide a basis for further research on the optimal design of structural parameters and the determination of safe configurations of the lifting system.

几何形状对气垫升力的影响研究

One of the crucial and challenging issues for researchers is presenting an appropriate approach to evaluate the aerodynamic characteristics of air cushion vehicles(ACVs)in terms of system design parameters.One of these issues includes introducing a suitable approach to analyze the effect of geometric shapes on the aerodynamic characteristics of ACVs.The main novelty of this paper lies in presenting an innovative method to study the geometric shape effect on air cushion lift force,which has not been investigated thus far.Moreover,this paper introduces a new approximate mathematical formula for calculating the air cushion lift force in terms of parameters,including the air gap,lateral gaps,air inlet velocity,and scaling factor for the first time.Thus,we calculate the aerodynamic lift force applied to nine different shapes of the air cushions used in the ACVs in the present paper through the ANSYS Fluent software.The geometrical shapes studied in this paper are rectangular,square,equilateral triangle,circular,elliptic shapes,and four other combined shapes,including circle-rectangle,circle-square,hexagonal,and fillet square.Results showed that the cushion with a circular pattern produces the highest lift force among other geometric shapes with the same conditions.The increase in the cushion lift force can be attributed to the fillet with a square shape and its increasing radius compared with the square shape.

用lifting方法设计最优LPPR-FIR滤波器组

该文研究了如何用lifting方法构造线性相位完全重建有限脉冲响应(LPPR-FIR)滤波器组的优化设计问题,即如何转化为一个二次型优化问题.然后把该方法推广到M带FIR滤波器组,考虑在一种特殊情形中如何构造具有线性相位性质的M带PR-FIR滤波器组,最后列举了几个例子说明如何用lifting方法构造M带LPPR-FIR滤波器组。

Influence of Anteroposterior Symmetrical Aero-Wings on the Aerodynamic Performance of High-Speed Train

The running stability of high-speed train is largely constrained by the wheel-rail coupling relationship,and the continuous wear between the wheel and rail surfaces will profoundly affect the dynamic performance of the train.In recent years,under the background of increasing train speed,some scientific researchers have proposed a new idea of using the lift force generated by the aerodynamic wings(aero-wing)installed on the roof to reduce the sprung load of the carriage in order to alleviate the wear and tear of the wheel and rail.Based on the bidirectional running characteristics of high-speed train,this paper proposes a scheme to apply aero-wings with anteroposterior symmetrical cross-sections on the roof of the train.After the verification of the wind tunnel experimental data,the relatively better airfoil section and extension formof anteroposterior symmetrical aero-wing is selected respectively in this paper,and the aero-wings are fixedly connected to the roof of the train through the mounting column to conduct aerodynamic simulation analysis.The research shows that:compared with the circular-arc and oval crosssections,this paper believes that the crescent cross-section can form greater aerodynamic lift force in a limited space.Considering factors such as aerodynamic parameters,ground effect,and manufacturing process,this paper proposes to adopt aero-wings with arc type extension form and connect them to the roof of the train through mounting columns with shuttle cross-section.When the roof of the train is covered with aero-wings and runs at high speed,the sprung load of the carriages can be effectively reduced.However,there are certain hidden dangers in the tail carriage due to the large amount of lift force,so,the intervention of the aero-wing lifting mechanism is required.At the same time,it is necessary to optimize the overall aerodynamic drag force reduction in the followup work.

Experimental and Numerical Investigation on the Aerodynamic Characteristics of High-Speed Pantographs with Supporting Beam Wind Deflectors

Aiming to mitigate the aerodynamic lift force imbalance between pantograph strips,which exacerbates wear and affects the current collection performance of the pantograph-catenary system,a study has been conducted to support the beam deflector optimization using a combination of experimental measurements and computational fluid dynamics(CFD)simulations.The results demonstrate that the size,position,and installation orientation of the wind deflectors significantly influence the amount of force compensation.They also indicate that the front strip deflectors should be installed downwards and the rear strip deflectors upwards,thereby forming a“π”shape.Moreover,the lift force compensation provided by the wind deflectors increases with the size of the deflector.Alternative wind compensation strategies,such as control circuits,are also discussed,putting emphasis on the pros and cons of various pantograph types and wind compensation approaches.

Bone block from lateral window-correcting vertical and horizontal bone deficiency in maxilla posterior site:A case report

BACKGROUND Lateral window approach for sinus floor lift is commonly used for vertical bone augmentation in cases when the residual bone height is less than 5 mm.However,managing cases becomes more challenging when a maxillary sinus pseudocyst is present or when there is insufficient bone width.In this case,we utilized the bone window prepared during the lateral window sinus lift as a shell for horizontal bone augmentation.This allowed for simultaneous horizontal and vertical bone augmentation immediately after the removal of the maxillary sinus pseudocyst.CASE SUMMARY A 28-year-old female presented to our clinic with the chief complaint of missing upper left posterior teeth.Intraoral examination showed a horizontal deficiency of the alveolar ridge contour.The height of the alveolar bone was approximately 3.6 mm on cone beam computed tomography(CBCT).And a typical well-defined'dome-shaped'lesion in maxillary sinus was observed on CBCT imaging.The lateral bony window was prepared using a piezo-ultrasonic device,then the bony window was fixed to the buccal side of the 26 alveolar ridge using a titanium screw with a length of 10 mm and a diameter of 1.5 mm.The space between the bony window and the alveolar ridge was filled with Bio-Oss,covered with a Bio-Gide collagen membrane,and subsequently sutured.Nine months later,the patient’s bone width increased from 4.8 to 10.5 mm,and the bone height increased from 3.6 to 15.6 mm.Subsequently,a Straumann^(■)4.1 mm×10 mm implant was placed.The final all-ceramic crown restoration was completed four months later,and both clinical and radiographic examinations showed that the implant was successful,and the patient was satisfied with the results.CONCLUSION The bone block harvested from the lateral window sinus lift can be used for simultaneous horizontal bone augmentation acting as a shell for good two-dimensional bone augmentation.

基于Lifting的小波变换通用硬件实现方法研究

文章提出了一套完整的基于Lifting算法小波通用硬件实现的流程。该方法系统分析了目前基于Lifting算法小波实现过程中的有限精度分析,基本一维、两维小波变换结构设计以及常用优化算法,提炼出了一套小波设计的通用方法。该文将以6/10小波变换为例介绍该方法的具体实现过程,为设计者提供了一整套设计一个高性能小波可遵循的流程,它可以应用于小波变换的硬件设计以及相关的基于小波变换的信号处理系统设计。

Analysis of Maximum Liquid Carrying Capacity Based on Conventional Tubing Plunger Gas Lift

China’s unconventional gas fields have a large number of low-productivity and low-efficiency wells, many of whichare located in remote and environmentally harsh mountainous areas. To address the long-term stable productionof these gas wells, plunger-lift technology plays an important role. In order to fully understand and accurately graspthe drainage and gas production mechanisms of plunger-lift, a mechanical model of plunger-liquid column uplift inthe plunger-lift process was established, focusing on conventional plunger-lift systems and representative wellboreconfigurations in the Linxing region. The operating casing pressure of the plunger-lift process and the calculationmethod for the maximum daily fluid production rate based on the work regime with the highest fluid recovery ratewere determined. For the first time, the critical flow rate method was proposed as a constraint for the maximumliquid-carrying capacity of the plunger-lift, and liquid-carrying capacity charts for conventional plunger-lift withdifferent casing sizes were developed. The results showed that for 23/8 casing plunger-lift, with a well depth ofshallower than 808 m, the maximum drainage rate was 33 m3/d;for 27/8 casing plunger-lift, with a well depth ofshallower than 742 m, the maximum drainage rate was 50.15 m3/d;for 31/2 casing plunger-lift, with a well depthof shallower than 560 m, the maximum drainage rate was 75.14 m3/d. This research provides a foundation for thescientific selection of plunger-lift technology and serves as a decision-making reference for developing reasonableplunger-lift work regimes.

改良LIFT手术联合自体富血小板PRP凝胶技术治疗肛瘘的临床研究

目的:探讨改良括约肌间瘘管结扎术(LIFT)手术联合自体富血小板PRP凝胶技术治疗肛瘘的临床疗效。方法:随机将2021年5月至2023年5月在我院接受治疗的62例肛瘘患者分为对照组和观察组,31例一组。对照组采用改良LIFT手术治疗,观察组予以改良LIFT手术联合自体富血小板PRP凝胶技术治疗。随访两个月,比较两组住院时间,创面愈合时间,创面瘢痕面积,临床疗效,术后疼痛评分,肛门功能评分,并发症发生率。结果:观察组的住院时间和创面愈合时间均短于对照组,创面瘢痕面积少于对照组(P<0.05)。观察组治疗有效率为96.77%,高于对照组的80.65%(P<0.05)。观察组术后1天、7天VAS评分及术后1、2个月Wexner评分均低于对照组(P<0.05)。观察组术后并发症发生为6.45%,低于对照组的25.81%(P<0.05)。结论:肛瘘采用改良LIFT手术联合自体富血小板PRP凝胶技术治疗效果突出,可以缓解术后疼痛,改善肛门功能,减少并发症,促进预后恢复,值得临床推广应用。

LIVING A HAPPY LIFE,ENJOYING THE PRIMARY HUMAN RIGHT

Seventy-five years after the UN proclaimed the Universal Declaration of Human Rights as a common standard of achievements for all people and all nations,China has carved out a unique path of human rights development with historic achievements,lifting hundreds of millions of people out of poverty.In China,human rights are no abstract concept but tangible progress seen in the improvement of people’s life and life expectancy.The development and practice of human rights in China has four distinctive features:it is people-centric,autonomous,comprehensive,and sustainable.In particular,people’s rights to subsistence and development has been guaranteed,their right to be the masters of their country is better reflected,and the rights of all ethnic people and all groups have been more comprehensively fulfilled.

lift⁃off制程PEB温度对负性光阻显影后截面Profile的影响

本文研究了lift⁃off(揭开-剥离)制程曝光后烘烤温度(post exposure bake,PEB)对负性光阻显影截面Profile(光刻胶结构)的影响。结果表明:在保留原有PEB盘面加热的方式前提下通过增加PEB盘盖加热功能进行烘烤,通过控制PEB盘面温度可调整光阻关键尺寸(critical dimension,CD)及截面Profile形貌,通过控制PEB盘盖加热可调整截面Profile光阻顶端形貌及强度,可显著改善负性光阻显影后截面Profile难以调整的问题。另外,不同的盘面温度、不同盘盖温度以及不同的显影时间相互配合,可以实现一种负性光阻产生不同截面光刻胶结构效果,可以实现同种光阻lift⁃off制程多样化。