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利用热场动力学的方法研究了具有热噪声的相干态和压缩态中场正交分量的高阶涨落和高阶压缩.利用测量相位算符讨论了这些热化态中相位的高阶涨落.从而得到在有限温度下这些态的低阶及高阶涨落与温度的关系和压缩特性与温度的关系.由于实际的场态总是在一有限的温度下,所以讨论温度对涨落和压缩的影响是很有意义的.
关键词: 相似文献
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本文针对铟锌氧化物薄膜晶体管(IZO TFT)的低频噪声特性与变频电容-电压特性展开试验研究,基于上述特性对有源层内局域态密度及其在禁带中的分布进行参数提取.首先,基于IZO TFT的亚阈区I-V特性提取器件表面势随栅源电压的变化关系.基于载流子数随机涨落模型,在考虑有源层内缺陷态俘获/释放载流子效应基础上,通过γ因子提取深能态陷阱的特征温度;基于沟道电流噪声功率谱密度及平带电压噪声功率谱密度的测量,提取IZO TFT有源层内局域态密度及其分布.试验结果表明,带尾态缺陷在禁带内随能量呈e指数变化趋势,其导带底密度N1TA约为3.42×10~(20)cm~(-3)·eV-,特征温度TTA约为135 K.随后,将C-V特性与线性区I-V特性相结合,对栅端寄生电阻、漏端寄生电阻、源端寄生电阻进行提取与分离.在考虑有源层内局域态所俘获电荷与自由载流子的情况下,基于变频C-V特性对IZO TFT有源层内局域态分布进行参数提取.试验结果表明,深能态与带尾态在禁带内随能量均呈e指数变化趋势,深能态在导带底密度NDA约为5.4×10~(15)cm~(-3)·eV~(-1),特征温度TDA约为711 K,而带尾态在导带底密度NTA约为1.99×10~(20)cm~(-3)·eV~(-1),特征温度TTA约为183 K.最后,对以上两种局域态提取方法进行对比与分析. 相似文献
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顺序统计量将累积概率与数据排序后的位置建立相关联系,可用于估计数据分布的累积概率.鉴于不同气候要素概率分布存在着不同程度的偏态特征,基于偏态分布条件下的累积概率函数,通过理论推导和数值模拟建立了与偏态指数相关的位置参数的回归模型,从而给出了基于数据偏态特征的经验百分位估计公式.利用1980年-2009年全球夏季逐日平均温度资料,进一步对比分析了偏态百分位估计方法与Jenkinson方法下得到的第90个百分位值所对应的温度排序后位置的差异.
关键词:
顺序统计量
偏态分布
百分位 相似文献
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在分析双洞相关退激发对双洞态退激发的贡献较小的基础上,依据辐射-俄歇-双俄歇级联退激发模型(RACDA)研究了Mg1+(1s-1)(K壳层单洞态镁离子)和Mg2+(1s-2)(K壳层双洞态镁离子)的退激发过程,计算了它们的末电离态离子的分布,并与辐射-俄歇级联退激发模型的结果进行了比较.RACDA模型计算的Mg1+(1s-1)的4价末电离态离子的相对丰度较大,而辐射-俄歇级联退激发模型(RAC)的结果中就没有出现4价离子;两种模型计算Mg2+(1s-2)的6价末电离态离子的丰度非常大,而RAC模型下的Mg2+(1s-2)退激发后不产生6价离子.
关键词:
双洞态退激发
RACDA退激发模型 相似文献
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利用共生纠缠度研究了一个推广Jaynes Cummings模型中两原子纠缠的时间演化和有限温度下系统热纠缠态. 结果表明,腔场中两原子展现出周期性的纠缠演化过程,演化周期随原子偶极 偶极相互作用强度的增大而减小;在有限温度下,系统的共生纠缠度随温度的升高而降低,当趋近临界温度时,系统纠缠现象消失,这一临界温度值与原子偶极-偶极相互作用强度成正比. 对于典型的实验数据,临界温度约在10-5K数量级. 此外,在这种Jaynes Cummings模型中存在量子相位转变.
关键词:
Jaynes Cummings模型
原子纠缠态
热纠缠态
共生纠缠度
偶极 偶极相互作用 相似文献
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提出并研究两种新的量子光场态:位移二项式态和位移负二项式态.讨论了两种量子态的光子数分布、亚泊松分布特性.结果表明:位移二项式态是介于相干态与位移粒子数态之间的一种量子中间态,在不同参数下可表现亚泊松分布和超泊松分布;位移负二项式态是介于相干态与位移Susking Glogower位相态之间的量子中间态,它只表现超泊松分布.研究了它们与二能级原子在强度耦合情况下相互作用原子反转的动力学演化.
关键词: 相似文献
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利用Kinani-Daoud方法构造了非谐振子势的Gazeau-Klauder(GK)相干态和Klauder-Perelomov(KP)相干态,表明两种相干态在非线性谐振子势下具有完全不同的形式,并对两种相干态的完备性以及各自构成的Hilbert空间进行了讨论. 对相干态的Mandel Q参数的研究表明:GK相干态服从亚Poisson统计分布,KP相干态服从超Poisson统计分布.
关键词:
非谐振子
Gazeau-Klauder相干态
Klauder-Perelomov相干态 相似文献
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Masaru Nakamura Hiroshi Kutami Yuh Shiohara 《Physica C: Superconductivity and its Applications》1996,260(3-4):297-304
Single crystals of NdBa2Cu3O7−δ (Nd123) have been successfully grown by the top-seeded solution-growth (TSSG) method in 1%, 21% and 100% oxygen partial pressure atmosphere ((P(O2) = 0.01 atm, P(O)2) = 0.21 atm and P(O2) = 1.00 atm). Ba---Cu---O solvent with a Ba to Cu ratio of 3:5 was used in a Nd2O3 crucible. Nd is supplied by the reaction between the molten solvent and the Nd2O3 crucible. Compositions of Nd123 single crystals grown in different oxygen partial pressure atmospheres were analyzed by inductivity coupled plasma atomic emission spectrometry (ICP-AES) and confirmed to be Nd:Ba:Cu = 1.01:1.97:3.00 for P(O2) = 0.01 atm, Nd:Ba:Cu = 1.07:1.95:3.00 for P(O2) = 0.21 atm and Nd:Ba:Cu = 1.10:1.90:3.00 for P(O2) = 1.00 atm, respectively. The Nd123 single crystals grown in different oxygen partial pressure atmospheres were annealed in a pure oxygen gas flow, and the temperature dependence of the DC magnetization for these crystals was measured using a superconducting quantum interference device (SQUID) magnetometer. The Nd123 single crystal grown in P(O2) = 0.01 atm, and annealed at 340°C for 200 h showed a steep superconductive transition at 96 K. On the other hand, the Nd123 crystal grown in P(O2) = 0.21, 1.00 atm and, annealed at 340°C for 200 h exhibited a broad transition at 92 K for P(O2) = 0.21 atm and at 88 K for P(O2) = 1.00 atm, respectively. Therefore for Nd123 single crystal production with high quality superconductive characteristics, a low oxygen partial pressure atmosphere during crystal growth is found to be effective for minimizing the substitution of Nd ions into Ba sites. 相似文献
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An arrangement is described for generating at various pressures a filamentary, axially symmetric thermal arc of high stability. The arc's composition is wholly determined by the initial composition of the gas used. The radial temperature distribution of the arc in air was studied over the pressure range from 0.26 to 6 atm. At a current of 10 amps., the temperature in the axial region of the arc in air varies between 15 000 and 20 000° K, depending upon the pressure. At a distance of 0.4–0.5 mm from the axis of the discharge, the temperature drops to 5000° K.In conclusion, the authors wish to express their sincere gratitude to M. A. El'yashevich for his interest. 相似文献
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Using the isothermal ablation-stabilized arc model of Kovitya and Lowke [1], the high-current arcing behavior in tubes made from nylon or boric acid can be predicted from the tube length and radius. In the analyses of such arcs that occur in expulsion fuses and circuit breakers, the physical properties of the vapors formed from the ablated liner materials are required. Values of viscosity, thermal and electrical conductivities, density, specific heat, enthalpy, and sonic velocity for nylon and boric acid plasmas have been calculated for pressures of 1, 10, and 100 atm (1 atm = 101.3 kPa) over the temperature range from 5000-30 000 K. 相似文献
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An experimental and theoretical study on ablation controlled arcs in cylindrical tubes is presented. Measuring techniques for stagnation pressure, electric field strength, mass ablation rate, and arc cross section are described with which a comprehensive set of experimental data is obtained for blackened PTFE as a reference material. These data are interpreted with an isothermal two-zone model that consistently accounts for the balance of mass and axial momentum and yields simple scaling laws for the arc characteristics. Consistent agreement with the experimental data is found for an arc temperature TA = 19 000 ± 2000 K, a vapor layer temperature Tv = 3400 ± 200 K, and a transparently radiated fraction of the arc power of v = 0.32 ± 0.03. The vapor temperature can be explained with a photoablation mechanism. The ablation arc model allows quantifying of the phenomena related to nozzle clogging in gas-blast circuit breakers, namely flow blocking and reverse flow heating. How these phenomena determine the pressure rise in self-blast circuit breakers is shown. 相似文献
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Serbetci I. Nagamatsu H.T. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1990,18(1):91-101
An experimental investigation of the steady-state low current air arcs in a dual-flow nozzle system is presented. The cold flow field with no arc was determined for various nozzle geometries, i.e. two- and three-dimensional and orifice nozzles, and nozzle pressure ratios. Supersonic flow separation and oblique and detached shock waves were observed in the flow field. Using a finite-element computer program, the Mach number contours were determined in the flow field for various nozzle-gap spacings and pressure ratios. In addition, the DC arc voltage and current measurements were made for an electrode gap spacing of ≈5.5 cm and current levels of I ≈25, 50, and 100 A for the three nozzle geometries. The arc voltage and arc power increased rapidly as the flow speed increased from zero to sonic velocity at the nozzle throat. The shock waves in the converging-diverging nozzles resulted in a decrease in the overall resistance by about 15% 相似文献
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The swelling of Na-Montmorillonite is simulated by Monte Carlo molecular simulations in NPzzT and μVT ensembles, in two sedimentary basin conditions of 423 K at 750 atm and 483 K at 1050 atm and by using the CLAYFF force field [J. Phys. Chem. B 108, 1255–1266 (2004)]. The CLAYFF force field predicts a one, two-layer stable hydrate under 423 K at 750 atm and a one-layer stable hydrate under 483 K at 1050 atm with the stable basal spacings of 12.54 and 12.44 Å. The adsorbed water molecules are 45.22 and 41.92 per clay layer, with water densities of 0.28 and 0.26 g/cm3 and total energy of 2.11 and 3.65 kcal/mol of water. The predicted structure of Na-Montmorillonite are consistent with those reported in literature for high temperature and pressure conditions, however the results did not indicate a one-layer hydrate as the stable phase under basin conditions of 423 K at 750 atm [Clays Clay Miner. 34, 385 (1986)]. This work allows addressing the issue of the effect of basin condition on the structure of Na-Montmorillonite hydrate. 相似文献
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Abstract
The near-field structure of strongly buoyant jet issuing from a square nozzle at low Froude and Reynolds numbers is studied by using LIF flow visualization and time-resolved scanning PIV. These experimental techniques allow the visualization of unsteady three-dimensional flow phenomenon occurring in the near-field of strongly buoyant jet. It is found that the buoyant jet is unstable to the positive buoyancy forces, which promote the inflow motion near the nozzle exit. The surrounding low temperature fluid moves into the nozzle inside along the nozzle corner and mixes with the high temperature fluid deep into the nozzle. Then, the flow pattern inside the nozzle becomes highly complex to promote the laminar to turbulent transition of the jet. The statistical flow characteristics of the strongly buoyant jet are evaluated from the scanning PIV measurement, and the result indicates the presence of axisymmetric distributions of mean flow and velocity fluctuations in the circle of diameter equal to the square side of the nozzle. 相似文献20.
对某大型核反应堆非能动安全壳冷却系统(PCS)中安全壳外部的热环境进行了研究。建立了安全壳外部狭长空间的自然对流换热计算模型,基于Navier-Stokes(N-S)方程进行了求解,同时研究了安全壳出口高度对非能动安全壳冷却系统冷却性能的影响规律。结果表明:在标准大气压下、进口空气温度308.15K时,基准型安全壳按面积加权的出口平均温度为330.33K,引射的冷却空气质量流量为275.85kg/s,冷却空气带走的热量为6160kW;随着安全壳出口高度的增加,安全壳出口质量流量、换热量不断增加,但变化曲线斜率不断降低,最后趋于平缓,同时,衡量冷却空气有效冷却能力的温度效率线性降低,流动损失线性增大,兼顾换热量与流动损失存在一个最优解。 相似文献