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安徽贝母鳞茎不同部位的切块均可通过组织培养再生成完整的植株。不同组织及器官的发生需经不同培养基的诱导。鳞茎的休眠状态可为低温所打破。对鳞茎不同部位的再生能力进行了比较。对其愈伤组织形成、组织分化、器官发生以及在此过程中淀粉粒的变化及其生理意义进行了研究。 相似文献
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本文是一项有关大学英语网考改革对听力教学的预期反拨作用的实证研究。首先,在对国内外预期反拨作用进行综述的基础上提出一个符合中国大学英语网考改革实际的预期反拨作用模型,然后从教学管理者视角研究大学英语网考改革对听力教学的预期反拨作用。 相似文献
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如今,城市普遍存在道路拥堵、事故频发等交通问题,而随着互联网、无线通信及感应器等技术的发展,人们只需要通过车联网,即可满足安全、娱乐、导航、互动、通讯、远程控制和路况感应识别等多项需求,实现人、车、基站多方互动,构筑和谐交通生态系统,从而彻底改变人们的出行模式,重新定义汽车的DNA。 相似文献
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Multi-band microwave metamaterial absorber based on coplanar Jerusalem crossesMulti-band microwave metamaterial absorber based on coplanar Jerusalem crosses 下载免费PDF全文
The influence of the gap on the absorption performance of the conventional split ring resonator (SRR) absorber is investigated at microwave frequencies. Our simulated results reveal that the geometry of the square SRR can be equivalent to a Jerusalem cross (JC) resonator and its corresponding metamaterial absorber (MA) is changed to a JC absorber. The JC MA exhibits an experimental absorption peak of 99.1% at 8.72 GHz, which shows an excellent agreement with our simulated results. By simply assembling several JCs with slightly different geometric parameters next to each other into a unit cell, a perfect multi-band absorption can be effectively obtained. The experimental results show that the MA has four distinct and strong absorption peaks at 8.32 GHz, 9.8 GHz, 11.52 GHz and 13.24 GHz. Finally, the multi-reflection interference theory is introduced to interpret the absorption mechanism. 相似文献
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前科消灭制度,是世界各国共同认可和采纳的一项基本刑法制度,属于刑罚消灭制度的重要类型之一。我国刑事立法和其他民事、行政立法中都有大量关于前科的制度规定,但是却鲜见有与之相配套的前科消灭规定。前科制度的规定给犯罪人,特别是未成年人犯带来巨大的负面影响,从而致使行为人在一次犯罪之后,终身被贴上犯罪"标签",丧失许多平等的就业、升学的权利,在法律地位上与普通社会公民相比较呈现出不平等的状态。未成年人犯是极其特殊的一类犯罪人。在我国现有的刑事政策环境下构建具有中国特色的未成年人前科消灭制度是具有极其重大而深远的意义的。本文拟从理论和现实层面对该制度设计的价值取向做出初步探讨。 相似文献
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给定简单图G1和G2,G1的顶点标记为v1,v2………,vn1.图G1和G2的冠图G1.G2被定义为取n1个G2的拷贝,然后连接vi与相应的G2的第i个拷贝中的每一个点(i=1,2………,n1)所得到的图.在文献[2]中,对连通图G1和任一正则图G2,S.Barik,S.Pati和B.K.Sarma给出了G1.G2的邻接谱的完整的表达式.继文献[2]的工作进一步考虑当G2是非正则图时冠图G1.G2的邻接谱.本文完全确定了冠图G1.Km1,m2的邻接谱,其中Km1,m2是完全二部图. 相似文献
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The influence of the gap on the absorption performance of the conventional split ring resonator(SRR) absorber is investigated at microwave frequencies. Our simulated results reveal that the geometry of the square SRR can be equivalent to a Jerusalem cross(JC) resonator and its corresponding metamaterial absorber(MA) is changed to a JC absorber. The JC MA exhibits an experimental absorption peak of 99.1% at 8.72 GHz, which shows an excellent agreement with our simulated results. By simply assembling several JCs with slightly different geometric parameters next to each other into a unit cell, a perfect multi-band absorption can be effectively obtained. The experimental results show that the MA has four distinct and strong absorption peaks at 8.32 GHz, 9.8 GHz, 11.52 GHz and 13.24 GHz. Finally, the multi-reflection interference theory is introduced to interpret the absorption mechanism. 相似文献