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121.
ITER blanket design has progressed significantly since 2001, which resulted in a reduction in cost and an increase in performance with respect to FDR 2001. One of the most important improvements is the new coolant flow configuration in the shield block ( SB ) . In the current design TM, the cooling circuit in the SB is a matrix of radial holes which are arranged in eight poloidal rows. The rows are fed in parallel by front headers and back drilled collectors, and merge in four couples through the front header. These four couples of rows are linked in series by transverse holes. In the current design, a special shape of flow driver is mounted inside the radial hole, and coolant flows through clearance between the driver and drilled radial hole, which allows achieving a high coolant velocity,  相似文献   
122.
考虑了超磁致伸缩棒的对称有间隙滞回特性,建立了相应的超磁致伸缩材料执行器的动力学模型。通过渐进法分析,得到超磁致伸缩材料执行器运动相应的近似解析式。通过数值模拟,发现对称有间隙滞回非线性振动系统具有复杂的分叉和混沌行为。  相似文献   
123.
研制了一种多气隙电阻板室原型并建立了相关的测试系统.利用宇宙线测试系统和欧洲核子中心的试验束装置T1?0对其性能进行了测试,给出了初步结果.时间分辨达到70ps,对最小电离粒子的探测效率大于95%.  相似文献   
124.
一种新型双间隙输出腔的理论和实验研究   总被引:1,自引:1,他引:0       下载免费PDF全文
 从双间隙分离腔的色散关系式出发,通过数值计算求出了分离腔中IM010模对应的谐振频率,并给出了腔内轴向电场的分布图,证实了分离腔中存在着电场反相的π模场。因此,可以将其用作电场反相的双间隙输出腔,来实现双间障提取。并用2.5维粒子模拟程序——卡拉特(KARAT)程序对这种分离腔输出回路进行了粒子模拟和优化设计。通过详细的冷测和调试实验,研制出了中心频率为3.74GHz、QL值为7.8的低QL值双间隙输出腔。  相似文献   
125.
The complete flexural vibration band gaps are studied in the thin plates with two-dimensional binary locally resonant structures, i.e. the composite plate consisting of soft rubber cylindrical inclusions periodically placed in a host material. Numerical simulations show that the low-frequency gaps of flexural wave exist in the thin plates. The width of the first gap decreases monotonically as the matrix density increases. The frequency response of the finite periodic thin plates is simulated by the finite element method, which provides attenuations of over 20dB in the frequency range of the band gaps. The findings will be significant in the application of phononic crystals.  相似文献   
126.
Field emission from single-walled carbon nanotube (SWNT) nonwoven has been investigated under high vacuum with different vacuum gaps. A low turn-on electric field of 1.05\,V/$\mu $m is required to reach an emission current density of 10 $\mu $A/cm$^{2}$. An emission current density of 10 mA/cm$^{2}$ is obtained at an operating electric field of 1.88\,V/$\mu $m. No current saturation is found even at an emission current of 5\,mA. With the vacuum gap increasing from 1 to 10 mm, the turn-on field decreases monotonically from 1.21 to 0.68\,V/$\mu $m, while the field amplification is augmented. The good field-emission behaviour is ascribed to the combined effects of the intrinsic field emission of SWNT and the waved topography of the nonwoven.  相似文献   
127.
根据具有叶顶间隙的直叶栅和正、反弯叶栅壁面流动的墨迹显示以及横截面内气动参数测量,应用拓扑学原理,分析了端壁与叶片表面拓扑结构。与直叶栅比较,叶片正弯消除了上通道涡分离线,并使二次涡由闭式分离转变为开式分离,而叶片反弯仅影响奇点位置、旋涡强度与尺度。  相似文献   
128.
庄飞  吴良  何赛灵 《中国物理》2002,11(8):834-838
The plane-wave expansion method is used to calculate the band structure of a two-dimensional photonic crystal formed by a hexagonal structure of anisotropic cylinders. Two cylindrical inclusions in the unit cell have two different radii, R1 and R2 (R12). By reducing the symmetry of the structure and choosing appropriately parameters R2 and s=R1/R2 (s<1), we obtain six large complete bandgaps, among which three are over 0.05 ωe (where ωe=\frac{2πc}{a}) in the high region of the normalized frequency (however, one of these over 0.065 ωe is not stable). There are two other stable complete bandgaps in the low-frequency region.  相似文献   
129.
The concept and analysis method of photonic crystals and band gaps are introduced into one-dimenslonal (1D) ordered mesoporous materials. MCM-41 type of materials are treated theoretically as photonie crystals. The formation of band gaps is exhibited and confirmed by a calculation of transfer matrix technique. PBG was found around 9-42 nm in soft X-ray region. The photonie band-gap was predicted to be dependent on incident direction, pore size and lattice constant. The mesoporous materials with different pore sizes and different lattice constants have different band-gap widths.  相似文献   
130.
High density phase transitions in a 4-dimensional Nambu-dona-Lasinio model containing a single symmetry breaking order parameter coming from the fermion-antifermion condensates are researched and expounded by means of both the gap equation and the effective potential approach. The phase transitions are proven to be second-order at a high temperature T; however at T = 0 they are first- or second-order, depending on whether A/m(0), the ratio of the momentum cutoff A in the fermion-loop integrals to the dynamical fermion mass m(0) at zero temperature, is lessthan 3.387 or not. The former condition cannot be satisfied in some models. The discussions further show complete effectiveness of the critical analysis based on the gap equation for second order phase transitions including determination of the condition of their occurrence.  相似文献   
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