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51.
无芯模旋压旋轮轨迹曲线对其成形精度影响的仿真研究 总被引：1，自引：0，他引：1
研究目的：验证无芯模旋压工艺可行性,同时深入探究此新型工艺机理,研究并获取旋轮轨迹曲线参数化控制及其对于零件成形精度的影响趋势。创新要点：基于贝塞尔曲线实现对于无芯模旋压旋轮轨迹曲线的参数化控制;通过构建包括成形与回弹工艺过程的无芯模旋压仿真模型,研究参数化轨迹曲线对成形件壁厚及形状精度的影响趋势及关系,同时对成形过程变形区应力应变进行了深入探究分析。研究方法：1．基于三次贝塞尔曲线实现对于旋轮轨迹曲线的拟合以及参数化控制（图3）;2．利用LSDYNA软件实现对无芯模旋压成形及回弹工艺综合仿真及其过程、结果数据的提取;3．研究不同参数化轨迹曲线下成形件壁厚及形状精度变化趋钟（图12和13）,获取量化轨迹曲线对于零件成形精度影响关系（表3）,并通过增加实验组验证所获关系模型;4．提取成形过程中及成形后板料变形区应力及应变数据（图14-19）,深入探究上述变形机理。重要结论：凹轨迹曲线下,坯料中部出现最大减薄及变形程度,且降低曲线曲率,形状精度提高;凸轨迹曲线下,最大减薄及变形区域出现在坯料后部,且降低曲线曲率,壁厚及形状精度均提高。 相似文献
52.
逆向工程技术及快速成型技术在2008年江苏省大学生实践创新训练计划项目中的应用,采用图片转三维的逆向工程技术进行电极的三维建模,在三维转实体的近似处理中,选取wrl格式以保留渲染的色彩,在分层软件中以每层0.05mm切片,最终使用三维打印式快速成型机z-printer450实现了以江苏信息职业技术学院院标图案为样本的＂养正修能＂的院标电极的设计及快速制造。 相似文献
53.
<正> 一、转化推广难的主要表现 技术转让难 十余年来,全国省部级以上的农业科技成果,推广了30～40％,大面积推广应用的仅有15％。高校种植业科技成果,推广率不会高于这个水平。 产品销售难 农业科技新产品,尽管显示了先进性,但是农民在没有试用之前,是不会冒然购买的,你试我试,真正推广开非要三五年。 产权保护难 农业科技成果,只要转让推广出去,就无法保密,被侵权是常有的事。 相似文献
54.
DETERMINATION OF ACYCLOVIR IN PHARMACEUTICAL AND URINE BY HIGH PERFORMANCE CAPILLARY ELECTROPHORESIS
Zhang Shusheng 《中国科学院研究生院学报》1997,(2)
Acyclovir[9-(2-hydroxyethoxymethyl)guanine,ACVjisanantiviralsubstanceeffec-tiveagainstherpessimpIexandvaricellazosterviruses1'2.SeveralmethodsfortheanalysisofACVinplasma,serum,urineandointmentshavebeendescribedincludingradioim-munoassay',ELISA',HPLC"'andspectroph0tometry'.Highperf0mancecapilIaryelec-trophoresis(HPCE)hastheadvantagessuchasrapidity,economyandso0n,andhasbeenusedfortheseparationanddeterminationofvariousclassesofdrugs'.Inthispaper,anovelmeth0dbyHPCEf0rdeterminingACVinpha… 相似文献
55.
ＳＩＮＧＬＥ－ＳＷＥＥＰＯＳＣＩＬＬＯＰＯＬＡＲＯ－ＧＲＡＰＨＩＣＡＮＡＬＹＳＩＳＯＦＰ－ＮＩＴＲＯＢＥＮＺＯＩＣＡＣＩＤ￥ＹｕａｎＺｈｕｏ－ｂｉｎ；ＨａｎＦｅｎｇ－ｍｅｉ；ＣｈｅｎＹｏｎｇ；ＷｕＹａｎ－ｘｉａ（ＧｒａｄｕａｔｅＳｃｈｏｏｌ，Ｃｈｉｎ... 相似文献
56.
Multiband orthogonal frequency division multiplexing (MB-OFDM) ultra wide-band (UWB) is a novel wireless communication technology. It has many advantages and is being actively researhed. In this study, we constructed and implemented a simulation model of UWB communication systems in Simulink. We found the MB-OFDM UWB system has the best performance in distance between 4 m to 10 m without the line-of-sight requirement. 相似文献
57.
ZHAO Peng MU Xin YAO Jin-hua WANG Yong YANG Xiu-tai 《重庆大学学报(英文版)》2007,6(3):172-176
We established an integrated and optimized model of vehicle scheduling problem and vehicle filling problem for solving an extremely complex delivery mode-multi-type vehicles, non-full loads, pickup and delivery in logistics and delivery system. The integrated and optimized model is based on our previous research result-effective space method. An integrated algorithm suitable for the integrated and optimized model was proposed and corresponding computer programs were designed to solve practical problems. The results indicates the programs can work out optimized delivery routes and concrete loading projects. The model and algorithm have many virtues and are valuable in practice. 相似文献
58.
张家口学院成为2018年北京冬奥组委授牌的首批11家北京2022年冬奥会和冬残奥会培训基地之一后,学院开设了冰雪运动课程,培养与冰雪运动相关的志愿性人才和工作者,为满足地域发展需求不断努力。在发展过程中,学校教学质量的高低和教学方法手段的应用及教学效果的有效评价有着紧密的关联,将PDCA循环法引入张家口学院冰雪运动课程教学质量管理中,通过多次的循环发展来发现教学过程中存在的问题并提出解决办法,使冰雪运动课程的教学质量不断改进和提升。 相似文献
59.
碎裂QRS波对急性心肌梗死患者的短期预后评估(英文)简 总被引：2，自引：1，他引：1
Qin-hui SHENG Chih-Chi HSU Jian-ping LI Tao HONG Yong HUO 《Journal of Zhejiang University. Science. B》2014,15(1):67-74
This study is aimed to investigate the clinical significance and the short-term prognostic value of frag- mented QRS （fQRS） for patients with acute myocardial infarction （AMI）. Three hundred patients with AMI were tested with retrospective analysis on the patients＇ clinical information, hospitalized treatment, fQRS onset time, location of lesions, and other relevant data, in order to assess the relationship between the presence of fQRS and its prognosis. The rates of malignant cardiac arrhythmia, left ventricular systolic dysfunction （LVSD）, and mortality in the positive fQRS group were 13.6%, 29.2%, and 23.7%, respectively, with all showing a p value 〈0.05. For the ST segment elevation myocardial infarction （STEMI） subgroup, all the rates showed significant differences with a p value 〈0.01, while for the non-STEMI （NSTEMI） subgroup showed no significant differences. In patients with a positive fQRS, there were no differences in malignant cardiac arrhythmia between patients with and without percutaneous coronary in- tervention （PCI） （p〉0.05）. As for the LVSD and mortality, the p values between patients with and without PCI were 0.031 and 0.000, respectively, suggesting statistical significance. The results imply that AMI patients with positive fQRS especially for the patients with STEMI had higher rates of malignant cardiac arrhythmia, LVSD, and mortality than the non-fQRS group. Patients of AMI with positive fQRS, who underwent early revascularization, could lower the incidence of the cardiovascular event. In addition, the presence of fQRS could be used as an indication of early in- tervention treatment for patients. 相似文献
60.
Xu CAI Qun-xing HUANG Moussa-mallaye ALHADJ-MALLAH Yong CHI Jian-hua YAN 《浙江大学学报(A卷英文版)》2015,(1):70-80
目的：寻找金属污染物在热转化过程中的生成和迁移规律,为可燃固体废弃物高效清洁能源化利用提供科学指导。方法：飞灰采自两台不同类型在运行固废焚烧炉;采样位置位于烟气净化系统之前以规避干扰;利用同
步辐射技术中的X射线近边吸收结构和吸收精细结构谱图结合热力学模拟对金属锌的形态进行分析和研究。结论：1.金属锌在炉排炉飞灰小颗粒上主要以氯化物形式存在,而在流化床飞灰小颗粒上是以铝硅酸盐为主;2.燃烧过程中的高硫氮比能够有效减少锌有毒形态的生成;3.硅、铝和钙基材料是锌蒸汽有效的吸附剂。 相似文献
步辐射技术中的X射线近边吸收结构和吸收精细结构谱图结合热力学模拟对金属锌的形态进行分析和研究。结论：1.金属锌在炉排炉飞灰小颗粒上主要以氯化物形式存在,而在流化床飞灰小颗粒上是以铝硅酸盐为主;2.燃烧过程中的高硫氮比能够有效减少锌有毒形态的生成;3.硅、铝和钙基材料是锌蒸汽有效的吸附剂。 相似文献