Power supply for generating frequency-variable resonant magnetic perturbations on the J-TEXT tokamak

To further research the response of the tearing mode(TM) to dynamic resonant magnetic perturbation(DRMP) on the J-TEXT tokamak, a modified series resonant inverter power supply(MSRIPS) with a function of discrete variable frequency is designed for DRMP coils in this study. The MSRIPS is an AC–DC–AC converter, including a phase-controlled rectifier, an LC filter, an insulated gate bipolar transistor(IGBT) full bridge, a matching transformer, three resonant capacitors with different capacitance values, and three corresponding silicon controlled rectifier(SCR) switches. The function of discrete variable frequency is realized by switching over different resonant capacitors with corresponding SCR switches while matching the corresponding driving frequency of the IGBT full bridge. A detailed switching strategy of the SCR switch is put forward to obtain sinusoidal current waveform and realize current waveform smooth transition during frequency conversion. In addition, a resistor and thyristor bleeder is designed to protect the SCR switch from overvoltage. Manufacturing of the MSRIPS is completed, and the MSRIPS equipment can output current with an amplitude of 1.5 kA when its working frequency jumps among different frequencies. Moreover, the current waveform is sinusoidal and can smoothly transition during frequency conversion. Furthermore, the transition time when the current amplitude rises from zero to a steady state is less than 2 ms during frequency conversion. By using the MSRIPS, the expected discrete variable frequency DRMP is generated, and the phenomenon of the TM being locked to the discrete variable frequency DRMP is observed on the J-TEXT tokamak.     

场反等离子装置60 kV角向箍缩线圈绝缘结构设计

本文简要介绍场反等离子装置60 kV角向箍缩线圈绝缘在设备运行中的关键作用，结合运行工况阐述了角向箍缩线圈绝缘关键参数和制作工艺的选择过程，并对其力学性能以及绝缘性能进行测试和分析；在样件分析基础上，制作了相应的样机，并进行了性能测试。结果表明：合理优化主绝缘厚度，适当增大绝缘圆角，可减小线圈角部场强41%，使线圈使用寿命延长9倍，击穿电压高于设计电压的20%；对比ANSYS计算结果和样件测试结果发现，浸渍固化过程中选用8 MPa压力可有效增强粘接力。     

TiO_2负载光催化剂的制备与结构性能研究

用sol-gel法制备褐铁矿/TiO2光催化剂,通过XRD、SEM测试表征和降解实验表明,褐铁矿/TiO2光催化剂在褐铁矿颗粒表面负载上一层较为均匀的TiO2膜,且核/膜结构结合较为牢固;在pH=4、光催化剂投加量5 g/L、光照时间为2 h时,CODCr去除率达到70%(由251 mg/L降为78.3 mg/L),具有较好的降解效果;此光催化剂经重复利用后样品回收率较高,催化活性仍较好.     

基于推挽式带伪直流母线拓扑的光伏逆变器设计

针对中小功率光伏并网发电系统的特点,在分析比较常用拓扑方案的基础上,采用推挽式带伪直流母线的拓扑结构作为光伏并网逆变器的主电路。文中重点阐述了主电路的工作原理和关键电路元件的参数设计,并对整流二极管的缓冲和工频逆变器的控制进行了相应的探讨。最后通过实验结果验证了理论分析的正确性。     

絮凝-光催化降解联合处理造纸废水

用sol-gel法制备褐铁矿/掺Fe3+TiO2光催化剂,通过测试表征和回收实验表明,褐铁矿颗粒表面负载上一层较为均匀的TiO2膜,且核/膜结构较为牢固;利用絮凝剂和自制光催化剂对造纸废水进行絮凝-光催化降解联合处理实验表明,经过联合处理CODCr去除率达到94%,CODCr由3 000 mg/L降为183 mg/L,符合国家排放标准。     

蜂王幼虫的研究进展

本文综述了蜂王幼虫的生产、贮存、营养成分和生物学功能等方面的研究进展,并对蜂王幼虫开发利用前景进行了展望。     

Numerical simulation of plasma response to externally applied resonant magnetic perturbation on the J-TEXT tokamak

Nonlinear magnetohydrodynamic (MHD) simulations of an equilibrium on the J-TEXT tokamak with applied resonant magnetic perturbations (RMPs) are performed with NIMROD (non-ideal MHD with rotation, open discussion). Numerical simulation of plasma response to RMPs has been developed to investigate magnetic topology, plasma density and rotation profile. The results indicate that the pure applied RMPs can stimulate 2/1 mode as well as 3/1 mode by the toroidal mode coupling, and finally change density profile by particle transport. At the same time, plasma rotation plays an important role during the entire evolution process.     

A brief review of the development and optimization of the three-dimensional magnetic configuration system in the J-TEXT tokamak

The three-dimensional (3D) magnetic configuration system in the J-TEXT tokamak has featured in many experimental studies. The system mainly consists of three subsystems: the static resonant magnetic perturbation (SRMP) system, the dynamic resonant magnetic perturbation (DRMP) system and the helical coil system. The SRMP coil system consist of two kinds of coils, i.e. three six-loop coils and two five-loop coils. It can suppress tearing modes with a moderate strength, and may also cause mode locking with larger amplitude. The DRMP coil system consists of 12 single-turn saddle coils (DRMP1) and 12 double-turn saddle coils (DRMP2). Its magnetic field can be rotated at a few kHz, leading to either acceleration or deceleration of the tearing mode velocity and the plasma rotation. The helical coil system consists of two closed coils, and is currently under construction to provide external rotational transform in J-TEXT. The 3D magnetic configuration system can suppress tearing modes, preventing and avoiding the occurrence of major disruption.     

Stress and Thermal Analysis of the In-Vessel Resonant Magnetic Perturbation Coils on the J-TEXT Tokamak

A set of four in-vessel saddle coils was designed to generate a helical field on the J-TEXT tokamak to study the influences of the external perturbation field on plasma. The coils are fed with alternating current up to 10 kA at frequency up to 10 kHz. Due to the special structure, complex thermal environment and limited space in the vacuum chamber, it is very important to make sure that the coils will not be damaged when undergoing the huge electromagnetic forces in the strong toroidal field, and that their temperatures don’t rise too much and destroy the insulation. A 3D finite element model is developed in this paper using the ANSYS code, stresses are analyzed to find the worst condition, and a mounting method is then established. The results of the stress and modal analyses show that the mounting method meets the strength requirements. Finally, a thermal analysis is performed to study the cooling process and the temperature distribution of the coils.     

基于场反位形的磁约束氘氘脉冲聚变中子源方案设计

聚变中子源可以真实反映材料在聚变中子辐照下的特性变化,对于开展聚变堆材料测试具有重要意义。基于加速器打靶原理的国际聚变材料辐照装置（IFMIF）与理想聚变中子源在聚变中子能谱等方面仍有一定差异,因此需对聚变中子源方案进行新的思索。本文围绕磁约束聚变中子源开展了磁场位形、加热方案设计与相关计算,分析了场反等离子体在两级级联磁压缩后的等离子体温度、密度演化过程及相应的中子产额,并研究了考虑双流体效应与有限拉莫尔半径效应后场反等离子体倾斜模、旋转模等磁流体不稳定性的抑制情况,最终给出了氘氘脉冲聚变中子源的关键物理参数。研究结果表明,该中子源有望获得年均2 MW/m2以上的高通量密度的聚变中子,能够满足商业聚变示范堆材料测试要求;经功率估算显示,基于场反位形进行两级级联磁压缩的新型聚变中子源方案还具备成为氘氘脉冲聚变能源的应用前景。