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不等螺旋角立铣刀的抗振性及设计研究 被引量:1
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作者 许晋 庞安定 +4 位作者 刘鹏程 左小陈 李屏 王社权 彭志华 《工具技术》 2018年第8期111-115,共5页
分析传统立铣刀工作时产生振动的原因,提出不等螺旋角立铣刀抗振原理。根据其结构特点,推导出不等螺旋角立铣刀在圆周方向上等分隔处的刃长的计算公式。通过瓦尔特机床公司tool-studio加工软件模拟铣刀的槽形截面图,验证了公式的正确性... 分析传统立铣刀工作时产生振动的原因,提出不等螺旋角立铣刀抗振原理。根据其结构特点,推导出不等螺旋角立铣刀在圆周方向上等分隔处的刃长的计算公式。通过瓦尔特机床公司tool-studio加工软件模拟铣刀的槽形截面图,验证了公式的正确性,并举例论述公式的应用。根据公式分析了立铣刀各刃等分隔的影响因素,并得出铣刀的直径、螺旋角和齿间夹角对立铣刀刃长的影响最大,从而提出不等螺旋角立铣刀结构设计的思路。为了验证不等螺旋角立铣刀抗振性,进行拐角铣削和侧铣对比切削试验,结果表明:与传统立铣刀相比,不等螺旋角立铣刀具有抑制振动和提高工件表面粗糙度的优点。 展开更多
关键词 振动 抗振原理 不等螺旋角立铣刀 tool-studiao 等分隔 螺旋角 齿间夹角 刃长
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An improved resampling algorithm for rolling element bearing fault diagnosis under variable rotational speeds
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作者 赵德尊 李建勇 +1 位作者 程卫东 温伟刚 《Journal of Southeast University(English Edition)》 EI CAS 2017年第2期150-158,共9页
In order to address the issues of traditional resampling algorithms involving computational accuracy and efficiency in rolling element bearing fault diagnosis, an equal division impulse-based(EDI-based) resampling a... In order to address the issues of traditional resampling algorithms involving computational accuracy and efficiency in rolling element bearing fault diagnosis, an equal division impulse-based(EDI-based) resampling algorithm is proposed. First, the time marks of every rising edge of the rotating speed pulse and the corresponding amplitudes of faulty bearing vibration signal are determined. Then, every adjacent the rotating pulse is divided equally, and the time marks in every adjacent rotating speed pulses and the corresponding amplitudes of vibration signal are obtained by the interpolation algorithm. Finally, all the time marks and the corresponding amplitudes of vibration signal are arranged and the time marks are transformed into the angle domain to obtain the resampling signal. Speed-up and speed-down faulty bearing signals are employed to verify the validity of the proposed method, and experimental results show that the proposed method is effective for diagnosing faulty bearings. Furthermore, the traditional order tracking techniques are applied to the experimental bearing signals, and the results show that the proposed method produces higher accurate outcomes in less computation time. 展开更多
关键词 rolling element bearing fault diagnosis variable rotational speed equal division impulse-based resampling
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Analysis of bulked segregants to identify molecular markers linked with cocoon weight and cocoon shell weight in the silkworm Bombyx mori L
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作者 SateeshKumar 徐孟奎 +2 位作者 陈玉银 Ponnuvel,K.M Datta,R.K 《Journal of Zhejiang University Science》 CSCD 2002年第3期348-354,共7页
Two silkworm strains viz, B20 A (high cocoon shell ratio) and C.Nichi (low cocoon shell ratio) were sib mated for 10 generations to determine the homozygosis. Both bulked segregant analysis(BSA) and near isogenic line... Two silkworm strains viz, B20 A (high cocoon shell ratio) and C.Nichi (low cocoon shell ratio) were sib mated for 10 generations to determine the homozygosis. Both bulked segregant analysis(BSA) and near isogenic lines (NIL) studies were done to identify the RFLP markers closely linked to cocoon shell parameters. Three hundred and fifty two random clones were identified as the low copy number sequence and used for identification of Restriction Fragment Length Polymorphic (RFLP) marker linked to cocoon weight and cocoon shell character. In the bulk segregant analysis, DNA from the parents (B20 A, C.Nichi), F 1 and F 2 progeny of high shell ratio (HSR) and low shell ratio (LSR) were screened for hybridization with the random clones. Polymorphic banding pattern achieved through southern hybridization with different probes indicated the probable correlation of polymorphism with high and low cocoon shell character which are possible landmarks in identifying the putative marker(s) for the cocoon shell character. Out of the 100 probes tried with parents, F 1, F 2 and their bulks, 10 probes were found to be closely linked to cocoon shell characters. 展开更多
关键词 Restriction fragment length polymorphic (RFLP) Molecular marker Bombyx mori L Shell ratio Bulked segregant analysis(BSA) Near isogenic lines
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