对话农机手

"三夏"时节,田野麦浪滚滚,收割机机声隆隆。小麦2010年又是丰收年,农民们看着丰收景象,满脸洋溢着喜盈盈的笑,农机手们开着联合收割机,满怀着甜蜜的快乐,机欢唱,人开心,同奏着麦收的"欢乐颂"!     

精致的设计 诗意的栖居——专访青岛绿城建筑设计有限公司暖通主任工程师张小峰

<正>刚出火车站,天空幽蓝,空气湿润,寻路未果,索一路人,依其指点,穿过条条巷道,眼前便是一望无际的大海了,心情一下子就豁然开朗,长途的疲累此时早已     

一种值得称羡的生活方式

正在德国的大街上经常可以看到,既有白发老者,又有高挑美女,还有身着蓝色工装的技工,腋下都夹着一本书,目光祥和,举止优雅,慢悠悠行走着,公交车上、一些乘客静静地读书,有时还能见到在等候乘客的片刻,司机也在翻阅书本。自古以来,读书好学的     

2013 价值远航

时光如水,岁月如歌。《现代零部件》即将走过悠悠十载春秋,在2013年迎来创刊十周年。十年来,《现代零部件》在广大作者和读者的支持与帮助下,脚踏实地,一步一个脚印,取得了令人欣喜的成绩。回首创刊之初,她犹如一株树苗,在春天萌发嫩芽,沐浴阳光雨露,伴随季节更替,历经重重洗礼,     

工程机械发展对液压技术的需求动向

进入21世纪以来,世界工程机械发展处于低迷状态,平均增长率有下降趋势,2001年比2000年下降2.2%,自2003年开始,工程机械销售额有一定增长,以日本为例,2003年销售额约100亿美元,比2002年增长15%,其中内需为5247亿日元,增长4%,外需(出口)为6296亿日元,约占总销售额的1/2,增长20%,外需增长主要是中国及亚洲市场需求激增的缘故。由于日本对废气排出量有新的限制,使设备更新量增大,例如,液压挖掘机增长8%,汽车起重机增长12%。据日本建设机械协会预测,2004年日本工程机械将增长9%,达110亿美元,其中液压挖掘机增长16%,小型挖掘机增长6%,由于建设项目…     

MATLAB和数控机床在凸轮反求中的应用

文中通过运用三轴数控铣床和寻边器,用极坐标编程,对旋切机的凸轮轮廓进行测点,利用MATLAB对所测数据进行处理,找出轨迹方程,利用CAD/CAM软件的公式曲线等工具建模,最终生产出高品质的产品,不但提高了产品的质量,降低了成本,主要为企业找到了反求的捷径.     

开拓创新强化服务大力发展机械工业标准化

中国机械工业联合会是为适应国家工业管理体制改革需要,经国务院同意、民政部批准,于2001年4月正式成立的综合性行业协会。按照国家标准委和国家发展改革委的授权,三年多来,特别是在2004年,我们以科学发展观为指导,以市场需求为导向,以为政府、为企业服务为宗旨,本着不“越位”、不“错位”、不“缺位”的工作原则,围绕振兴机械工业,开拓创新,强化服务,     

专栏征稿函 十载历程 十年成长 喜迎《现代零部件》创刊10周年

2003～2013时光如水,岁月如歌。《现代零部件》即将走过悠悠十载春秋,在2013年迎来创刊十周年。十年来,《现代零部件》在广大作者和读者的支持与帮助下,脚踏实地,一步一个脚印,取得了令人欣喜的成绩。回首创刊之初,她犹如一株树苗,在春天萌发嫩芽,沐浴阳光雨露,伴随季节更替,历经重重洗礼,一路茁壮成长。而今已有沉甸甸的十岁年轮,并在行业媒体中崭露头角。十年历程,您与我们携手并肩一起走     

产能过剩，天胶轮胎利润捆绑下行

天然橡胶、轮胎、汽车,从上到下,从源头到终端,彼此之间关系紧密,价格上有明显的联动性,在利润上也紧密相关,照常理来讲,天然橡胶价格下跌,轮胎的利润在较短时间上升,影响到汽车,也会令汽车行业受益,反之亦然。     

岚县初步实现马铃薯全程机械化生产

岚县位于山西省西北部,吕梁山北端高寒山区,地处黄河流域中部,属晋西北黄土高原山区.辖3镇9乡,面积1 514 km2,境内多为丘陵区,地势较为平坦,平均海拔1200 m以上,平均气温6.8 ℃,有效积温2 727 ℃,日温差14.7 ℃,年平均降雨为504.9 mm,无霜期为90～125 d.独特的自然条件,既是理想的马铃薯生产区域,又适宜机械化生产.全县粮田面积3万hm2,其中马铃薯每年种植面积均在1万hm2以上.占粮田面积的1/3,是农民收入的重要来源之一.实现马铃薯机械化生产具有得天独厚的优势.     

Effects of prebuckling deformations on the elastic flexural-torsional buckling of laterally fixed arches

The effect of the prebuckling in-plane deformations on the elastic flexural-torsional buckling of laterally fixed circular arches is studied in this paper. The finite strains and the energy equation for the flexural-torsional buckling of arches have been derived based on an accurate orthogonal rotation matrix. A closed form solution for the elastic flexural-torsional buckling resistance of laterally fixed arches in uniform bending, including the effects of the prebuckling deformations, is obtained. It is found that the notion that the prebuckling deformations increase the flexural-torsional buckling moment of an arch or of a beam is not necessarily correct for a laterally fixed arch or beam in uniform bending, in deference to a laterally pinned arch. When a laterally fixed arch is subjected to positive uniform bending, the effects of the prebuckling deformations decrease the buckling moment, and the reduction of the buckling moment increases with an increase of the included angle and of the out-of-plane slenderness ratio of the arch. When a laterally fixed arch is subjected to negative uniform bending, the effects of the prebuckling deformations decrease the absolute value of its buckling moment when the included angle is very small, but increase the absolute value of the buckling moment when the included angle exceeds a certain value. The increase in the absolute value of the buckling moment increases with an increase of the included angle and of the out-of-plane slenderness ratio of the arch. When the ratio of the out-of-plane to the in-plane second moments of area of the cross-section is not small, both the reduction of the buckling moment of a laterally fixed arch in positive uniform bending and the increase of the buckling moment of a laterally fixed arch in negative uniform bending, are substantial.     

车门静态强度的有限元分析模拟

轿车门系统结构设计与优化是整车开发过程中的重要环节。车门的强度直接关系到整车在冲击、碰撞等载荷下的安全问题,车门结构静态强度的计算分析,在车门结构设计进程中非常重要。文中首先简要介绍了静态强度所涉及到的非线性有限元的基本理论,然后以某中高级轿车前车门为例,利用计算机辅助分析车门的静态强度,考虑变形的非线性因素,通过对车门的非线性有限元求解来分析车门强度,由计算所得到的车门强度性能指标来指导车门的结构设计。     

DESIGN AND ANALYSIS OF NOVEL ACTIVE ACTUATOR TO CONTROL LOW FREQUENCY VIBRATIONS OF SHAFT SYSTEM

Aiming at providing with high-load capability in active vibration control of large-scale rotor system, a new type of active actuator to simultaneously reduce the dangers of low frequency flexural and torsional vibrations is designed. The actuator employs electro-hydraulic system and can provide a high and circumferential load. To initialize new research, the characteristics of various kinds of active actuators to control rotor shaft vibration are briefly introduced. The purpose of this paper is to introduce the preliminary results via presenting the structure, functions and operating principles, in particular, the working process of the electro-hydraulic system of the new actuator which includes a set of high speed electromagnetic valves and a series of sloping cone-shaped openings, and presenting the transmission relationships among the control parameters from control signals into the valves to active load onto shaft. The course of the work is dynamic, and a series of spatial forces and moments are put on the shaft to get an external resultant force to reduce excitations that induce vibration of shafts. By checking states of vibration, the actuator can control the impulse width and the interval of injection time for applying different control force to a vibration shaft in two circumference directions through the regulating action of a set of combination directional control valves. The results from simulating analysis and experiment show evidence of that this design can satisfy the case of active process of decreasing of flexural and torsional vibrations.     

INFLUENCE OF ROLL DIAMETERS ON DEFORMATION BEHAVIOUR OF HIGH TEMPERATURE SUPERCONDUCTING TAPE

During plastic process,the material flow is strongly influenced by the contact area between deformed workpiece and die.In rolling process,difference of roll diameter makes the contact area between roll and deformed tape different,which leads to different material flow and the distribution of powder density.A numerical modelling of the first rolling process for 61-filament high temperature superconducting tape is constructed and the influences of roll diameters on deformation behavior of the tape are discussed.It can be found that the BiSrCaCuO(BSCCO)powder in the center of the tape has higher relative density than those in the periphery of the tape during rolling process.With the increase of roll diameter,the length of the contact arc in the roll gap expands which lead to the in- creasing of transversal strain and the decreasing of the related longitudinal strain.It makes the value of longitudinal strain ratio decrease gradually,which decreases the possibility of occurrence of the transversal shear band,simultaneously it increases the risk of occurrence of longitudinal crack.     

基于生物质谱的蛋白质组学绝对定量方法研究进展

蛋白质组学定量方法包括相对定量和绝对定量两部分。相对定量蛋白质组学（也称比较蛋白质组学）是指对不同生理病理状态下细胞、组织或体液蛋白质表达量的相对变化进行比较分析;绝对定量蛋白质组学是测定细胞、组织或体液蛋白质组中每种蛋白质的绝对量或浓度。目前蛋白质组学的绝对定量方法主要有基于内标法的蛋白质组学绝对定量方法和基于质谱数据统计分析的非标记方法。蛋白质组学定量的信息可以帮助了解蛋白质在相互作用网络中所起的作用;通过对临床生物标记物绝对量的分析,可以帮助直观地判断疾病的发生和发展过程,这对于临床诊断和疾病治疗都具有现实的指导意义。     

Computer simulation of turbine oil oxidation. 2: Consumption of a hindered phenol antioxidant in laboratory oxidation tests and in service

The computer simulation study of consumption of di-tert-butyl p-cresol (DBPC) was extended to the oxidation of hexadecane/tetralin model oils under conditions of laboratory oxidation tests and in service. The oxidation lives of the model oils in the ALCOA oxidation test and the ASTM D2272 rotary bomb and D943 turbine oil oxidation tests were successfully predicted from the simulation study. The oxidation behaviour of the model oils is compared to that of a turbine oil used in actual service units. The model oil having 6 mass % of tetralin showed almost identical oxidation behaviour to the turbine oil when the same amount of DBPC was added (0.6 mass %). The calculation shows that the direct oxidation of antioxidants is the main process of antioxidant consumption in the laboratory oxidation tests as well as in the model oxidation system without metal catalysts. In most of the service units which operated at moderate conditions the calculation shows that the direct oxidation of antioxidants is also the main, process. As a consequence, the rate of antioxidant consumption does not depend much on the tetralin content in the model oils. The oxidation behaviour of the model oils in the service units which operate under severe conditions, such as in the high temperature regions of turbines, is calculated by setting a flow reactor model. The results of this calculation show in this case that the turbine oil degradation occurs mostly in the high temperature regions and that the rate of antioxidant consumption increases with an increased amount of tetralin in the model oils. This strong dependence on base oil composition can be attributed to the increased importance of antioxidant consumption through the inhibition of oxidation.     

The effect of basic nitrogen compounds on the tribological performance of sulphurised olefin

The effect of the molecular structure of basic nitrogen compounds on the lubricating properties of sulphurised olefin has been investigated using a Timken tester. X-ray Photoelectron Spectroscopy (XPS) and Energy Dispersive X-ray Analysis (EDAX) were used to study the chemical states of sulphur and nitrogen on the rubbed surfaces and the reaction rates of sulphur and iron separately. It was found that the antiwear and friction reduction properties of sulphurised olefin are greatly influenced by the different molecular structures of the basic nitrogen compounds. A composite additive package containing basic nitrogen compounds with sulphurised olefin can produce either synergistic or antagonistic effects, due to the influence of the different molecular structures of the basic nitrogen compounds. XPS analysis revealed that a tribochemical protective film containing nitrogen and sulphur was formed on the rubbed surface. EDAX analysis indicated that the reaction rates between elemental sulphur and iron were influenced by the different molecular structures of the basic nitrogen compounds. It was found that the apparent reaction rates of elemental sulphur and iron are related to the tribological characteristics of the additive package.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.     

铝合金中铁元素数字光谱快速分析

利用可见光谱数字化分析系统将铝合金中Fe元素Fe526.95nm分析谱线组谱图转变为数字化的电子谱图,使用计算机自动分析代替人眼视觉判断,解决谱图的量化分析和记录难题。对4种不同Fe元素含量的铝合金样品进行数字化分析测定,探索选用Fe526.95nm谱线作为分析谱线,选用Cu529.25nm谱线作为比较谱线进行定量测定的方法,数据显示分析谱线和比较谱线的强度比值与Fe元素含量成正比关系。研究数字化系统指导视场定位和谱线辨别的途径,降低可见光谱分析的技术难度并提高快速分析的可靠性。结果表明,数字化技术保持快速分析特点的同时可以达到定量分析目的,能够有效解决铝合金中Fe元素的快速定量分析及材料牌号鉴别问题。