Feasibility of Synchronously Straightening Working Line of Adjacent Open-cast Mines

Taking Heidaigou Open-cast Mine and Haerwusu Open-cast Mine in Zhungeer mining area as the research objects,this paper deeply analyzes the current mining status of the two mines.Based on the existing working line length,mining technology,transportation system,equipment configuration,transportation access and many other factors,it systematically discusses the feasibility of straightening the working line of adjacent open-cast mines.Through in-depth theoretical analysis,it establishes the mathematical model of impact indicators and cost calculation,and it is concluded that the work line straightening can be technically achieved.However,from the perspective of economic benefits,straightening the working line does not show obvious advantages.

RESEARCH ON STRAIGHTENING TECHNOLOGY CAM SYSTEM

Automatic straightening process is a nonlinear process, and affected by manyfactors. The straightening technology CAM system has been designed and built up to straightenshafts, which mainly consists of the straightening technology's database and the model ofstroke-controlled precise straightening calculation model. The operational test of the CAM systemhas been passed.

Innovation in the Computing System of Straightening Force

Currently in China, the computing system of the straightening force of the six-rollers straightening machine generally follows the traditional computing system. The force status of the traditional computing system for the straightening force deviates far away from the actual force status of the roller system in the six-rollers straightening machine. In the traditional system, the computing model of the straightening force of the six-roller straightening machine was based on the roller shape of hyperbola, which led to the length of the contacting line between the tube and the straightening roller to be excessively short, i.e., only 0.1~）.2 of the length of the roller. Thus the constructed computing system has relatively large difference from the actual measured result. To solve the above problems, flattening straightening and bend straightening are analyzed on the basis of materials mechanics and bend beam theory, the roll er shape using the envelope method of A.I4.~e：mKoB is generated, and a new computing system for straightening force in six-rollers straightening machine is built. The roller shape of the straightening roller, on which the new computing system for the straightening force is based, is designed according to the envelope method under the condition of ideally full contacting between the tube and the roller body of the straightening roller, therefore the new computing model accords with the practical status of straightening force. According to the comparison of the new computing system with finite element method and the actual measured result of straightening force, it has been proved that the computation accuracy of the new computing system for straightening force satisfies the practical requirements of engineering. New six-rollers straightening machines are designed and manufactured according to the new calculation system, and the new machines not only have higher precision and quality, but also have adopted the force sensor and computer and combined with the new computing system for straightening force to realize the fully automatic adjustment of the straightening machine. The new six rollers straightening machine have obtained notable economical and social benefits.

Longitudinal crack on slab surface at straightening stage during continuous casting using finite element method

Deformation behavior of slab at the straightening stage during continuous casting was simulated by the explicit dynamic finite element method,and the stress distribution along the width direction of the slab and its change regularity at slab center during continuous casting were obtained.The influence of distribution and change of stress on the propagation of longitudinal cracks on slab surface was discussed.The results show that the tensional stress appears on slab surface at the inner arc side and the compressive stress appears on slab surface at the outer arc side at stages 6-8 in straightening zone during continuous casting.Longitudinal cracks generally appear on slab top surface and do not appear on slab bottom surface,which are also observed in industry.

Multi-point flexible straightening process by reciprocating bending for metal profiles

A multi-point flexible straightening process characterized by reciprocating bending is proposed.Specifically,the process is analyzed in terms of deformation mechanism and verified by numerical simulations and physical experiments of the straightening of a series of metal profiles with different materials and initial shapes.Further,the relationship between the bending radius and the times of reciprocating bending required to unify the curvature is discussed,and the distribution of residual stress after straightening is analyzed.The results show that the reciprocating bending process can eliminate the difference of the initial curvature,make the curvature of each section tend to be uniform;the times of reciprocating bending to reach the uniform curvature decreases with the decrease of bending radius.The straightness of the straightened profile obtained from the experiment and simulation is less than 0.2%,demonstrating a good feasibility of this method.

Evaluation of straightening capacity of plate roll straightener

Straightening machine is widely used for improving the quality of the defective mild steel plates.In general,the capacity of straightening machine is affected by material properties,the initial shape of the incoming plate and the plastic ratio.The mechanics model describing the capacity of the machine was developed.The deviation of the straightening capacity curves was studied.Then,the presented model was evaluated by comparative study to filed production data.Finally,the influences of overstretch,straightening speed,strengthening coefficient,elastic modulus,width of the plate on the straightening capacity were studied.It is convenient to determine whether the plate can be straightened or not by a series of straightening capacity curves.The straightening speed,width of the plate and elastic modulus of the material are more sensitive to the straightening capacity than the strengthening coefficient.

The mathematic model of tension straightening process of magnesium alloy and experimental validation

The stress-strain curve of bending bar and the stress relax curve of AZ31 was obtained by a tension test using Gleeble-1500.The tension straightening process mainly consisted of the elastic loading-I and unloading stage,the elastic loading-II and unloading stage,and the elastic-plastic loading stage,which were based on the stretch force change during straightening.The circular bar straightening under one-dimensional bending was investigated and assumed to be linear strain-hardening elastic-plastic material.According to the elastic-plastic mechanics theory,the mathematical displacement-force model of a tension straightening process established,on which was based,the predicted displacement of tension straightening for various original deflection was calculated.The tension straightening experiment for AZ31 magnesium was conducted under the guidance of the predicted displacement.The experiment results present good straightness when there is a stress relaxation phenomenon or the temperature of tension straightening is 25℃.

The Role of Corrugation Die Parameters on the Mechanical Properties of Aluminum Alloy (AA 5083) Processed by Repetitive Corrugation and Straightening

The microstructure and mechanical properties of aluminium alloy (AA 5083) processed through Repetitive Corrugation and Straightening (RCS) was studied. The RCS process consists of corrugating a flat specimen with a pair of systematically grooved dies and straightening was done with two parallel flat dies. The aluminium samples were subjected to RCS process using two different die: Die I-semi grooved die with breath = height = 5 mm and θ = 30。 and Die II-semicircular profile with radius = 10 mm. The specimens were subjected to maximum 8 passes for die I but the other one went upto 14 pass. The grain refinement was studied from the microstructure examination using TEM. The mechanical properties such as tensile strength, hardness and the grain size were compared. The tensile strength and hardness were found increasing with respect to the number of passes. The tensile strength increased 25% in the sixth pass when compared to the parent material. But the strength and hardness values were reduced at 8th pass due to the surface cracks. The TEM studies showed that the Die-I is superior to Die-II in terms of grain refinement.

A Solution of Drawing Straightening Roller Curve by Conjugate Revolving Quadric Theory

Based on the theory of conjugate revolving quadric theory,the analytic method of calculating the straightening roller curve in the procedure of straightening the bar has been given. Meanwhile,the equations,which describe roller curve and the longitudinal section,are given and simulated in computer. A brief method of designing and drawing the straightening roller curve is introduced.

Analytical-Numerical Modeling Approach for Calculation of the Structural Distortions after Welding and Thermal Straightening

The analytic-numerical hybrid model for calculating welding distortions in large welded structures is presented. Objective of the analytical model is the calculation of the plastic strains and their distribution after welding and thermal straightening process. The consideration of the essential physical relations is put into discussion. Afterwards the obtained plastic strains by the analytical calculation are loaded on an elastic FE-model of the structure and the distortions of the whole structure are predicted. The consideration of welding and thermal straightening scenarios and the assembling stages is done by taking into account the intermediate variation of the strain state at every processing step. The model is intended to be used for solving industrial tasks, i.e. intending acceptable precision and calculation time as well as low simulation costs. The application of the model is demonstrated on structures with many welds and straightening spots.

清开灵注射液的临床应用及安全性研究进展

清开灵注射液是在传统古方安宫牛黄丸基础上研制而成的纯中药复方制剂,为临床常用的中药注射剂之一,具有清热解毒、化痰通络、醒神开窍等功效,主要用于热病、神昏、中风偏瘫、神智不清等治疗。现代研究表明,清开灵注射液具有解热抗炎、保护脑组织、保肝降酶等作用,在临床上广泛应用于脑血管疾病、呼吸系统疾病等多种治疗。通过对多年来已发表的关于清开灵注射液临床研究文献和不良反应报道的搜集整理,对清开灵注射液临床应用、不良反应及安全性进行系统的总结分析,为进一步开发和拓展清开灵注射液的研究应用奠定基础。

政府管理部门在科技中介机构发展中的作用

科技中介服务机构在加速科技成果转化、推动科技与经济结合、促进高新技术产业发展中的地位和作用越来越重要。必须科学界定管理部门在科技中介体系中的行为,重视政府对科技中介机构发展的引导作用,切实理顺政府管理部门与科技中介机构之间的关系,以促进科技中介机构健康发展。

藏传佛教在伏尔加河流域土尔扈特蒙古中的发展

文章结合各种文献探讨了17～18世纪藏传佛教在伏尔加河流域土尔扈特蒙古中的发展情况,认为藏传佛教在当地蒙古社会中的持续发展和整饬,不仅维护了蒙古统治者的自身利益,也有力地抵制了俄国政府的宗教分化政策,捍卫了民族独立,更为土尔扈特蒙古东返中国奠定了基础。

抽油杆助抽扶正器研制

为防止抽油杆管偏磨,提高泵效,延长井下抽油系统的使用寿命及检泵周期,研制了一种抽油杆助抽扶正器。将多个抽油杆助抽扶正器连接在抽油杆柱中,每一个抽油杆助抽扶正器相当于装在抽油杆上的可以开合的柱塞。下冲程时自动打开,上下畅通,只起扶正、防偏磨作用;上冲程时自动闭合,形成多个在油管中的大直径柱塞,随抽油杆一起上升,分担了作用在抽油泵柱塞上的压差,从而减少了柱塞与泵筒之间的漏失与磨损,可提高井下设备的寿命,延长检泵周期。

译界确实需要对话——评《文学翻译的理论与实践——翻译对话录》

本文对<文学翻译的理论与实践--翻译对话录>进行了评介,对这部作品的学术价值和现实意义作了充分的肯定,尤其对有关翻译的可能性和翻译的限度进行了全面的梳理.

闻一多的古籍文献整理观及其价值

在从事古籍文献整理的过程中,闻一多形成了自己的文献整理观:提出整理文献的"三项课题";树立真善美相统一的检验标准;确认整理文献是编纂文学史的最基本的工作。闻一多的文献整理观立足于传统又大胆冲破传统的束缚,既为中国文献学的发展开拓了新路,也对以后文献整理者有着深刻的启发作用与持久的示范效应。

50年回眸:建国以来的中国写作学

建国以来的中国写作学可分为３ 个时期：借鉴—徘徊时期（５０ 年代至７０年代末）、自觉—兴盛时期（８０ 年代）和综合—梳理时期（９０年代）。经过几代人的努力。

浅谈颈性眩晕的中医外治

颈性眩晕是颈性综合征中的一种常见类型,属中医"眩晕"、"头晕"等范畴,是一种常见病、多发病。临床上采用中西药物治疗往往疗程长,易复发,具有不同程度的副作用。该文介绍的温针隔姜灸、醒脑开窍法、磁圆针刺法、耳压针灸法、刺络拔罐法等中医外治疗法,有疗程短、见效快、不易复发、疗效稳定的特点。

大学生逆反心理的新特点与疏导

目前大学生的消极逆反心理出现了如下新特点:不受制客观事物性质、也不特别依赖情境影响、产生上的主观性;由对主流政治的厌烦,发展至抵触、质疑、否定,指向范围的扩张性甚至向普通生活泛化;表达方式呈激昂、狂热、破坏行为等直接性;表现的随意性令人惊讶。必须注意与独立意识相伴的反叛倾向的个体因素;社会阴暗面,还有同龄群体的相互激发感染的社会因素;形式内容方式手段都存在缺陷的教育因素。才能借鉴中外经验,进行有成效的疏导。