共查询到20条相似文献，搜索用时 15 毫秒
1.
王宁 《昆明师范高等专科学校学报》2010,32(2):43-47
昆明市晋宁县是典型的西部农业县,其城乡一体化农村劳动力就业到人力资本、就业服务机制等多种因素的制约。对此提出建议：1．统筹城乡产业发展,推进农业产业化,为农村劳动力转移就业创造条件;2．推进农村城镇化进程,促进农村劳动力转移就业;3．统筹城乡就业,建立统一的就业服务体系,为农村劳动力就业构建公平的环境;4．统筹城乡公共事业发展,增强农村劳动力抵御社会风险及市场风险的能力。 相似文献
2.
This paper puts forward a new method to achieve flux cored wire TIG welding and uses high-speed photography to analyze the droplet transfer behavior and forces acting on the droplet. The droplet transfer forms include bridging transfer, slag column guided transfer, and non-contact transfer; each of these forms may be observed as the melting position of the welding wire changes. The important role of surface tension in the process of droplet transfer is proposed using static force balance theory and pinch instability theory. The phenomenon of droplet backward swing during welding process could be attributed to the vapor recoil force produced by vapors from the droplet. The welding experiments show that the proposed welding process is stable and that the weld quality produced is good. 相似文献
3.
Autofocus method based on the analysis of image content information is investigated to reduce the alignment error resulting from mark positioning uncertainty due to defocus in microstructure layered fabrication process based on multilevel imprint lithography, The applicability of several autofocus functions to the alignment mark images is evaluated concerning their uniformity, sharpness near peak, reliability and measure computation efficiency and the most suitable one based on power spectrum in frequency domain (PSFD) is adopted. To solve the problem of too much computation amount needed in PSFD algorithm, the strategy of interested region detection and effective image reconstruction is proposed and the algorithm efficiency is improved. The test results show that the computation time is reduced from 0.316 s to 0.023 s under the same conditions while the other merits of the function are preserved, which indicates that the modified algorithm can meet the mark image autofocusing require-ments in response time, accuracy and robustness. The alignment error due to defocus which is about 0.5 μm indi-cated by experimental results can be reduced or eliminated by the autofocusing implementation. 相似文献
4.
In this paper, based on the principle of heat transfer and thermal elastic-plastic theory, the heat treatment process optimization scheme for face gears is proposed according to the structural characteristics of the face gear and material properties of 12Cr2Ni4 steel. To simulate the effect of carburizing and quenching process on tooth deformation and residual stress distribution, a heat treatment analysis model of face gears is established, and the microstructure, stress and deformation of face gear teeth changing with time are analyzed. The simulation results show that face gear tooth hardness increases, tooth surface residual compressive stress increases and tooth deformation decreases after heat treatment process optimization. It is beneficial to improving the fatigue strength and performance of face gears. 相似文献
5.
The resonant tunneling diode (RTD) is an ultra-highspeed and ultra-high frequency quantum-transport deviceaccompanied with negative differential resistance (NDR)I-Vcharacteristic originating fromresonant tunneling effect .The core structure of RTDis doubl… 相似文献
6.
利用PECVD生长技术制备a-Si/SiNx多层膜,利用解理技术获得干净平滑的截面.利用选择性化学腐蚀技术在横截面上制备出浮雕型一维纳米模板.通过控制多层膜子层的生长时间,得到线条宽度和槽状宽度均最小为20纳米的等间距模板,品质优于电子束制备的模板.以这种模板为基础,利用印章技术制作了硅基光栅. 相似文献
7.
徐美银 《扬州职业大学学报》2000,4(4):22-25
许多塑料模型腔用冷挤压成型,各种模具材料的性能差异会对塑料模型腔的冷挤压工艺及塑件精度产生影响。为提高工艺性和精度,对模腔最佳工艺斜度进行探索和研究,并以简明计算公式直接应用于塑料模型腔或塑件最佳工艺斜度设计。 相似文献
8.
徐美银 《扬州职业大学学报》2001,5(2):32-35
紧固模套是组合模具中最常使用的结构，由于装配前存在过盈以及工作过程中冲裁力的作用，设计时必须对紧固模套进行强度和刚度校核。本介绍这两种校核的一般方法，并用工程实例说明。 相似文献
9.
周铭杰 《广东轻工职业技术学院学报》2007,6(1):13-15,35
通过对洗衣机进水口塑件结构特点的分析,设计了洗衣机进水口注射模.重点阐述注射模的顺序脱模机构及工作过程,同时介绍了侧向分型抽芯机构抽拨力及斜导柱直径的计算. 相似文献
10.
介绍了覆盖件冲压成形仿真理论以及冲压工艺,对冲压仿真流程进行了阐述。采用CAE技术ETA\Dynaform对某汽车盒形件进行模拟仿真,分析仿真结果,对其中的影响因素压边力和拉延筋进行了改进和确定。通过使用仿真方法,对板料的冲压成形及时进行观察和了解,针对成形后可能出现的缺陷问题,提出解决方案。在模具结构设计阶段改进局部结构,缩短了模具设计开发周期,提高板料利用率,为汽车覆盖件冲压成形提供技术支撑。 相似文献
11.
Humans prefer (conditioned) rewards that follow greater effort (Aronson & Mills, 1959). This phenomenon can be interpreted
as evidence for cognitive dissonance (or as justification of effort) but may also result from (1) the contrast between the
relatively greater effort and the signal for reinforcement or (2) the delay reduction signaled by the conditioned reinforcer.
In the present study, we examined the effect of prior force and prior time to produce stimuli associated with equal reinforcement.
As expected, pressing with greater force or for a longer time was less preferred than pressing with less force or for a shorter
time. However, participants preferred the conditioned reinforcer that followed greater force and more time. Furthermore, participants
preferred a long duration with no force requirement over a shorter duration with a high force requirement and, consistent
with the contrast account but not with the delay reduction account, they preferred the conditioned stimulus that followed
the less preferred, shorter duration, high-force event. Within-trial contrast provides a more parsimonious account than justification
of effort, and a more complete account than delay reduction. 相似文献
12.
岳东 《黄河科技大学学报》2012,40(3):82-85
唐初,随着大量北方游牧民族的内附,河朔成为移民奥区,城傍一直是河朔藩镇的重要土壤。部分城傍则与农民融合为一,从事农业生产,转变成了农民,同时也为河朔带来了尚武风气。唐束黄巢大起义时,一些河朔农民加入了起义军,至五代和南宋初期,河朔农民成为抵御契丹南下的生力军,而河北忠义军也成为抵御金兵南下的主力。在河朔由胡化回归到汉化的历史发展过程中,民族融合起了关键的作用。 相似文献
13.
陈辉华 《宁波职业技术学院学报》2014,(6):86-90
为了避免数控折弯机加工板材工件时的表面压痕发生,实验中从板材工件的折弯方式、材料硬度、凹模结构、选择机床与模具的精度4个方面来分析板材工件折弯时的产生表面压痕的原因。结果表明,通过使用防压痕胶垫、单V凹模防压痕胶套、块状优力胶＋AT垫衬、硬质橡胶凹模和无压痕折弯凹模的方法来解决数控折弯时工件表面的压痕,达到产品质量要求。 相似文献
14.
随着网络技术的发展 ,信息不仅已经成为制造业发展的决定性因素 ,而且还是最活跃的驱动因素。在此背景下 ,分析了模具企业制造中的信息需求 ,从模具研制企业的特点出发 ,讨论了实施动态联盟的必要性和可能性 ;提出了模具研制企业在现有条件下动态联盟的类型、形式以及联盟的建立过程 ;讨论了基于 internet的模具企业动态联盟的具体组建方案以及其中的关键技术。 相似文献
15.
CHOI Jin-hwa JEON Byung-cheol KIM Gun-hee SHIN Bong-cheol LEE Honghee CHO Myeong-woo SEONG Eun-je PARK Dong-sam 《浙江大学学报(A卷英文版)》2006,7(9):1474-1481
INTRODUCTION Today, the manufacturing industry makes con- stant effort in order to construct an E-manufacturing system using information technology for effective production control, and then, it offers the integrated production control to the workers, the production managers, and the consumers, etc. (Lee, 2003; Choi, 2004). In the mould manufacturing industry, the process managers often request paperwork to know the information of the processes on CNC machine tools or they visit the shop… 相似文献
16.
叙述了冷挤压的工艺特点，对纯铝仪表零件的加工进行了工艺分析，计算冷挤力并选择压力机，阐述了冷挤压模具结构及设计要点。 相似文献
17.
采用物化活化工艺,以枣椰仁为原材料制作颗粒活性碳( GAC) ,制作过程主要有 6 个步骤: 清洗,烘干,粉碎,筛分,炭化和活化. 通过小试对新型 GAC 去除余氯的特性进行了研究,并将实验结果与 Langmuir和 Freundlich 等温方程进行了拟合. 通过理论和实验分析,考察了主要运行参数对吸附动力的影响. 结果表明: Langmuir 等温方程与实验数据最为吻合,说明其对余氯吸附为单层吸附. 新型 GAC 在余氯吸附方面具有巨大潜力,比传统的吸附剂更具竞争力. 采用托马斯扩展模型结合物质转移阻力对实验结果进行了验证,模拟结果与实验非常符合. 相似文献
18.
闫文贵 《河北能源职业技术学院学报》2005,5(3):59-61
二灰碎石基层与面层连续施工是加快施工进度、缩短工期,进一步挖掘出二灰材料独特性质的新方法,本文从基层是否有足够的强度来抵御面层连续施工时机械对其结构的破坏和施工工艺的合理选择两个方面阐述二灰碎石基层与面层能够连续施工原因。 相似文献
19.
高慧 《北京工业职业技术学院学报》2012,11(4):1-3,8
双分型面注射模,常用于点浇口进料的单型腔或多型腔(多用)的注射模,结构比较复杂。以"盖产品"的三板式注射模具结构设计为例,对双分型面注射模的典型结构进行分析与设计,总结了其设计要点,对其他复杂模具的设计具有很好的借鉴作用。 相似文献
20.
The pressure to reduce solar energy costs encourages efforts to reduce the thickness of silicon wafers. Thus, the cell bowing problem associated with the use of thin wafers has become increasingly important, as it can lead to the cracking of cells and thus to high yield losses. In this paper, a systematic approach for simulating the cell bowing induced by the firing process is presented. This approach consists of three processes: (1) the material properties are determined using a nanoidentation test; (2) the thicknesses of aluminum (Al) paste and silver (Ag) busbars and fingers are measured using scanning electron microscopy; (3) non-linear finite element analysis (FEA) is used for simulating the cell bowing induced by the firing process. As a result, the bowing obtained using FEA simulation agrees better with the experimental data than that using the bowing calculations suggested in literature. In addition, the total in-plane residual stress state in the wafer/cell due to the firing process can be determined using the FEA simulation. A detailed analysis of the firing-induced stress state in single crystalline silicon (sc-Si), cast, and edge-defined film-fed growth (EFG) multi-crystalline silicon wafers of different thicknesses is presented. Based on this analysis, a simple residual stress calculation is developed to estimate the maximum in-plane principal stress in the wafers. It is also proposed that the metallization pattern, Ag busbars and fingers screen printed on the front of a solar cell, can be designed using this approach. A practical case of a 3-busbar Si solar cell is presented. 相似文献