激光表面微造型工艺试验与应用

在声光调Q二级管泵浦固体光源（DPSS）Nd∶YAG激光器基础上,采用“单脉冲同点间隔多次”激光微加工工艺,对灰铸铁材料表面进行微造型加工。分析了激光波长、光斑距离、重叠面积系数及重复频率对微造型质量的影响。试验研究表明,该工艺能有效防止金属熔融和重铸现象,获得较为理想的微腔形貌和表面质量。分析了微加工断面形貌,表明微腔（槽）表面留有一层与基体结合良好的硬化层。通过4L88型柴油机激光珩磨缸套的性能试验研究表明,与普通平顶珩磨缸套相比,采用激光珩磨缸套,柴油机机油耗降低39.3%,漏气量降低30%,PM排放降低18.8%。     

普通车床珩磨高精度套筒的新方法

珩磨高精度套筒加工过程中通过套筒的装夹与旋转运动和珩磨头的往复进给运动及加压运动,能够保证零件加工精度的同时,减少设备制造的整体投资,该技术具有一定的独创性。本文就珩磨高精度套筒的原理和技术要求进行了分析,对普通车床珩磨高精度套筒的新方法展开了实践论证,将为普通车床珩磨高精度套筒提供新的思路。     

柴油机气缸套形状偏差预测方法

基于弹性理论和缸套变形的4个假定条件,以直径和长度分别为8.5×11cm、9.5×11cm、12×14cm的小尺寸缸套产品为研究对象,确定柴油机气缸套变形的计算和试验方法。计算和试验结果表明,四缸内燃机,缸套尺寸为9.5×11cm时有最大变形,缸套尺寸为12×14cm时有最小变形。沿下配合环带径向载荷的变化,是导致沿活塞行程高度缸套内壁形状改变的根本原因;弯矩不是导致内燃机缸套装配时缸套工作面变形的主要原因。计算曲线与试验测量结果一致。     

硬韧材料旋转超声复合电解加工设计与试验

【目的】各类陶瓷、硬质合金等高硬、高韧材料机械加工效率低且精度差（甚至难以加工）,为解决硬、韧等难加工材料精密、高效加工问题,提出旋转超声复合电解加工新技术。【方法】设计、构建旋转超声复合电解加工系统,分析、探讨此加工方式的材料去除机理;对旋转超声振动装置中的旋转超声主轴、压电换能器、变幅杆进行设计;运用ANSYS工具对压电陶瓷堆进行模态分析和谐响应分析。【结果】对超声振动系统进行优化设计,实测系统超声振幅最大可达23μm,满足试验要求;对陶瓷（PZT）和硬质合金（YT15）进行加工对比试验,试验表明,旋转超声复合电解可加工出精细表面结构,同时加工效率可提高50%以上。【结论】所设计的加工系统能够实现硬、韧等难加工材料的高效率、高精度加工,提高加工效率和工件表面质量,具有显著的技术优势。     

高硬材料旋转超声辅助电解加工设计与试验

【目的】满足高硬材料的加工需求,解决高硬材料难以加工、效率低下、刀具损耗率高的问题。【方法】课题组基于旋转超声加工和电解加工提出了旋转超声加工辅助电解加工的方法,不仅分析了加工原理,选择了加工参数,还优化设计了加工系统,对换能器和变幅杆综合材料、密度、频率、纵波声速等因素进行了具体参数设计。【结果】对高速钢进行了不同加工方式的电解平面加工试验,发现同等条件下,机械磨削加工的圆孔明显比另外两种加工方式加工的圆孔粗糙,而旋转超声辅助电解加工的圆孔不仅直径大,而且表面更加平滑。【结论】机械磨削的效率比另外两种加工方式低,旋转超声辅助电解加工的加工深度最好,材料去除率更高,得到的加工表面也更加平滑,对高硬材料的加工效果更好。     

汽缸套珩磨的技术要点

汽缸套镗削完后,为了提高汽缸套的加工质量和表面精度,还应在珩磨机上进行珩磨。 汽缸套的珩磨质量主要取决于珩磨规范,砂条材料,磨头的运动轨迹及负荷。     

300柴油机气缸套内孔加工质量控制

1引言300柴油机气缸套是柴油机关键零部件,其质量好坏直接影响到柴油机的质量。为提高300柴油机质量,对300柴油机气缸套精镗、珩磨内孔进行质量控制,降低Φ300内孔不合格率。2现状调查300柴油机缸套为300柴油机关键零件,缸套质量控制不稳定是影响车间一等品率的重要原因。①对××年7-12月份300柴油机气缸套(图纸要求尺寸Φ300)机加工不合格情况进行统计,见表1。表1不合格品情况表2各项不合格品所占比例②对缸套内孔加工不合格品进行归类,见表3。表3300柴油机缸套内孔加工不合格归类统计③根据以上统计做不良项目排列图,见图1。图1300柴油机…     

排水暗管外包材料渗透性与除氮效果试验研究

测定了5种排水暗管外包材料(麦秸秆、锯末、陶粒、沸石、纤维球)的透水特性,并分析了不同外包材料及其厚度的去氮效果。结果表明,各外包材料对氨态氮和硝态氮的去除能力存在差异,无机材料对氨态氮的吸附能力较强,有机材料对硝态氮的去除能力更好;10cm厚度时锯末除氮效果最好,去除率为55.1%,而在30cm厚度时沸石相对更好,去除率为76.2%;外包料的厚度对总氮的去除能力呈正相关关系,每增加10cm厚度,麦秸秆和锯末总氮去除率增加6%～8%,陶粒和沸石总氮去除率增加6%～28%,纤维球总氮去除率增加10%～20%。     

超声波振动辅助磁力研磨加工研究

根据研磨加工的材料去除模型,分析得到增加研磨压力是提高磁力研磨加工效率的可行手段。通过在单纯磁力研磨工艺中引入超声波振动,增加了研磨粒子的瞬时研磨压力。经实验证明,在超声振动辅助磁力研磨加工中,研磨粒子在水平切削和垂直冲击挤压运动的综合作用下,对工件材料的去除率高且表面质量均匀;加工效率较单纯磁力研磨工艺提高了约50%;工件表面粗糙度Ra可降至0.06 μm左右;电子显微镜观察发现其加工后工件表面形貌较单纯磁力研磨细密均匀;采用X射线干涉仪检测得知,经超声振动辅助磁力研磨加工后的工件材料（SUS304）表层的应力状态已由原始的残余拉应力+320 MPa变为压应力-40 MPa,有效提高了工件的疲劳强度。     

等离子表面改性缸套的技术研究

将国内外较为先进的等离子表面改性技术应用于内燃机缸套内表面处理,改善其表层金属组织结构,以达到强化缸套内表面硬度和耐磨性,提高缸套使用寿命的目的.     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

农村剩余劳动力就业问题的探讨

论述了我国农村剩余劳动力就业的意义，并针对我国农村剩余劳动力的现状，提出多渠道促进农村剩余劳动力就业的途径和办法。     

车用发动机润滑油失效规律与更换周期研究

研究在正常使用条件下１０Ｗ／３０－ＱＣ级润滑油用于某型车用发动机时所表现的失效规律,确认期服从两参数Ｗｅｉｂｕｌｌ分布,并给出分布的尺度参数η和形状参数ｍ之最佳线性无偏估计（ＢＬＵＥ）同时,还为定量分析,计算车用发动机润滑油的使用可靠性和合理确定其更换周期提供了一套可供借鉴的方法,并给出了具体的计算实例。     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

乡（镇）农业技术推广体系存在的问题及对策

乡（镇）农技推广体系是农业发展的关键。介绍朝阳市农业技术推广体系的现状,针对目前体制及运行机制、服务手段等方面存在的问题,提出适合朝阳市乡（镇）农技推广体系改革与发展的对策,以期对全省农技推广体系改革和发展起到一些借鉴作用。     

草莓的采收与贮藏

草莓果味酸甜爽口,营养价值高,为人们所喜爱的应市鲜果之一。由于草莓易受损伤和微生物侵染,因此其采收、贮藏过程极为重要。介绍草莓采收过程中的注意事项以及11种贮藏保鲜技术的实施步骤和操作方法,推介9种加工方式,为草莓产业化提供技术支持。     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.