排序方式: 共有23条查询结果,搜索用时 921 毫秒
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为了进一步提高门座式起重机控制系统的平稳性和可靠性,在研究传统的起重机控制系统的基础上,设计了基于PLC模糊自适应PID的起重机变频调速系统,利用先进的模糊自适应PID算法与PLC控制技术相结合实现智能变频控制。系统直接由PLC实现函数运算取代常规的查表方式,改善调速性能,实现了变频调速系统的快速控制;同时,通过PLC对起重机变频器进行无触点控制,有效提高了的准确可靠性。仿真结果表明:加入模糊自适应PID控制的起重机变频调速系统比传统系统响应速度快,超调量低于3%,更加平稳可靠;同时降低了起重机功耗,节能近20%,并有效延长了电动机的使用寿命。 相似文献
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In order to investigate the possibility of the recently observed X(5568) being a 0~+ tetraquark state, we make an improvement to the study of the related various configuration states in the framework of the QCD sum rules. Particularly, to ensure the quality of the analysis, condensates up to dimension 12 are included to inspect the convergence of operator product expansion(OPE) and improve the final results of the studied states. We note that some condensate contributions could play an important role on the OPE side. By releasing the rigid OPE convergence criterion, we arrive at the numerical value 5.57+0.35 for the scalar-scalar diquark-antidiquark 0~+ -0.23 Ge Vstate, which agrees with the experimental data for the X(5568) and could support its interpretation in terms of a 0~+ tetraquark state with the scalar-scalar configuration. The corresponding result for the axial-axial current is calculated to be 5.77+0.44 still consistent with the mass of X(5568) in view of the uncertainty. The feasibility of-0.33 Ge V, which isX(5568) being a tetraquark state with the axial-axial configuration therefore cannot be definitely excluded. For the pseudoscalar-pseudoscalar and the vector-vector cases, their unsatisfactory OPE convergence make it difficult to find reasonable work windows to extract the hadronic information. 相似文献
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纳米晶Sb掺杂Sn02(ATO)粉体的合成与表征 总被引:1,自引:0,他引:1
以Sn粉和Sb2O3为原料.采用共沉淀法制备了纳米ATO粉.TG—DSC及FTIR结果表明,450℃以前前驱体已失去全部水分.并完全转化为氧化物.XRD测量结果表明.所得ATO粉具有四方金红石结构.500℃焙烧后粉体的粒径为12nm.随着焙烧温度的升高.粉体的粒径增加.TEM测定结果表明,粉体的分散性很好.团聚很少.粉体的烧结性能良好.950℃时烧结5h即达到理论密度的97.3%.用霍尔系数法测定粉体的导电行为.表明该粉体具有良好的导电性能. 相似文献
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In this talk, we give a short review of our recent works on studying the singly heavy baryon, doubly heavy baryon, and triply heavy baryon Spectra from QCD sum rules. 相似文献
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Sb掺杂SnO_2(ATO)纳米晶的水热合成和导电性能 总被引:8,自引:0,他引:8
以Sn和SbI_3为主要原料,在120-170 ℃温和水热条件下合成了具有导电能力 的Sb掺杂SnO_2(ATO)透明导电纳米粉体,运用FT-IR, XRD, BET, TEM等手段对 粉体的形成过程进行了分析表征。实验结果表明,所合成的纳米ATO粉体均为四方 锡石结构,无其他杂相存在,晶粒大小在4-7nm之间,粉体呈单分散状态。比表面 积在137-184m~2·g~(-1)之间,随水热温度的升高,晶粒长大,比表面积下降,粉 体导电性能提高。该方法对于其他透明导电氧化物纳米粉体的合成具有借鉴意义。 相似文献