共查询到20条相似文献,搜索用时 15 毫秒
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晶闸管的擎住电流和维持电流对于晶闸管的工作有重要的影响.利用晶闸管的导通特性,从载流子的角度推导出擎住电流的计算公式;通过对NPN晶体管电流增益的分析,得到维持电流的表达式.将计算结果与Sentaurus TCAD软件仿真结果对比,发现两者符合较好,验证了计算公式的正确性. 相似文献
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半导体激光器(LD)是一种电流注入式电致发光器件,其工作特性和使用寿命主要取决于驱动电流源的性能优劣。本文作者设计了一种用于中、小功率LD的新型电流源,它的工作原理是电压/电流转换、电流放大和电流负反馈。输出电流在0~3A范围内可连续调节,当电流分别为2A和3A时,连续5小时内的电流变化量均小于1mA,相应的电流稳定度分别为5.0×10-4和3.3×10-4。另外,该电源还具有抗击浪涌击穿、断电保护和过流保护等多种功能。与以往的电源相比,该电流源具有原理简单、稳定性好等优点,在教学、科研和生产中有很好的应用前景。 相似文献
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使用超导电性恢复温度模型分析了 CICC型超导体的稳定性与界限电流的关系 ,推导出表明导体运行电流位于下界限电流区域的门限临界电流的表达式 ,给出了 HT- 7U极向场 PF线圈导体的一种设计方案的计算结果。 相似文献
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HE Han-Xin 《理论物理通讯》2001,36(3):285-286
By computing the axial-vector current operator equation,
we find the anomalous axial-vector curl equation besides the well-known
anomalous axial-vector divergence equation (the Adler-Bell-Jackiw anomaly)
and discuss its implication. 相似文献
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介绍了光学电流测量技术的发展情况,描述了目前几种主要的互感器结构及其基本原理,并对各自存在的问题及解决途径进行了讨论。从研究现状来看,块状玻璃型传感器技术相对成熟,已经有商业产品问世;混合型传感器测量精度较高,但传感头有源电路的供电技术复杂,还没有圆满的解决方案;全光纤型是光学电流互感器发展的最终目标,目前存在的主要问题是光纤的固有线性双折射难以处理,有赖于新型光纤材料及集成光学元件的进一步发展。最后综合评述了光学电流互感器技术的发展趋势及产业化前景。 相似文献
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Vortex density current in the Gross-Pitaevskii theory is studied. It is shown that the inner structure of the topological vortices can be classified by Brouwer degrees and Hopf indices of φ-mapping. The dynamical equations of vortex density current have been given. The bifurcation behavior at the critical points of the current is discussed in detail. 相似文献
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Recent investigations have shown that with varying the amplitude of the external force, the deterministic ratchets exhibit multiple current reversals, which
are undesirable in certain circumstances. To control the multiple reverse current to unidirectional current, an adaptive control law is presented inspired from the relation between multiple reversals current and the chaos-periodic/quasiperiodic transition of the transport velocity. The designed controller can stabilize the transport velocity of ratchets to steady state and suppress any chaos-periodic/quasiperiodic transition, namely, the stable transport in ratchets is achieved, which makes the current sign unchanged. 相似文献
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Experiments which have been undertaken over a number of years have shown that a rotating magnetic field can drive a significant
non-linear Hall current in a plasma. Successful experiments of this concept have been made with a device called rotamak. In
its original configuration this device was a field reversed configuration without a toroidal magnetic field but with a vertical
field to establish the MHD equilibrium. However, modifications have shown that current can also be driven if a central current-carrying
rod is used to provide an applied toroidal field. The new rotamak has then a spherical tokamak magnetic field structure.
Article presented at the International Conference on the Frontiers of Plasma Physics and Technology, 9–14 December 2002, Bangalore,
India. 相似文献
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In this letter, the parafermion fields constructed by current algebra are considered. It is proved that there must be a parafermion field with respect to each form of current algebra. We also obtain the corresponding representation and unitary relation of the parafermion field from any current algebra. 相似文献
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Nonreciprocal errors in fiber-optic current sensors, which are induced by environment fluctuations such as temperature and linear and angular vibrations, are specified. These errors in three current sensor configurations are evaluated and compared theoretically. The comparison indicates that the in-line sensor with strip waveguide modulator has the best resistance to the mentioned three environment fluctuations. Methods that may be used to suppress the nonreciprocal errors in different sensor configurations are suggested. 相似文献
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稳定的光谱不随电流变化而改变的白色有机发光器件 总被引:15,自引:4,他引:11
使用新材料构成了两种结构白色有机薄膜电致发光器件,一种是蓝色及红色发射在同一层中,另一种是蓝色发射和红色发射分别在两层中,器件结构分别为ITO/CuPc/NPB/JBEM(P):DCJT/Alq/MgAg(器件1)和ITO/CuPc/NPB/JBEM(P)/Alq:DCJT/Alq/MgAg(器件2)。这里(CuPc)是空穴注入层;N,N’-bis-(1-naphthyl)-N,N’-diphenyl-1,1’bipheny1-4-4’-diamine(NPB)是空穴传输层(HTL);9,10-bis(3’5’-diaryl)phenyl anthracene(JBEM)是蓝色发射层;tris(8-quinolinolato)aluminium complex(Alq)是电子传输层(ETL);DCJT是红色染料。在器件1中得到稳定的且色度不随电流增在而变化的白色发射。它的最大亮度为14850cd/m^2,最大效率2.88lm/W,色度x=0.31,y=0.38(从4mA/cm^2到200mA/cm^2),半亮度寿命为2860小时(初始亮度1000cd/m^2)。比较了两种结构的器件,蓝红色发射在同一层结构的器件,在亮度、效率及稳定性上都优于蓝红发射在不同层结构的器件。 相似文献
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EAST等离子体高约束模运行条件下,在等离子体边缘区域观测到明显的等离子体电流带.在EAST托卡马克装置非圆截面平衡位形下,使用射线追踪方法研究低混杂波高平行折射率N‖分量对电流驱动的影响.结果表明:当-8≤N‖≤-6时,平行折射率分量能够在小半径(0.7 < r/a < 1)区域驱动kA量级的等离子体电流.对于具有台基区、等离子体边缘温度更高的电子温度剖面,驱动电流的位置r/a>0.9.低混杂波朗道阻尼的理论分析与数值模拟结果一致.另外,高N‖低混杂波在等离子体边缘的功率沉积和电流驱动与电子温度分布和发射谱分布相关. 相似文献