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1.
用SQUID磁强计测得了Y0.8Pr0.2Ba2Cu3O7-δ单晶在外场平行于c轴条件下的磁化强度随温度的变化。在超导转变下,除了磁化强度是可逆的以外,由于磁通涨落而导致的磁化强度交叉发生在超导转变温度以下约2K处。利用Hao-Clem模型拟合可逆磁化强度得到了热力学临界场Hc(T)和金兹堡-朗道参数k。其它超导参数由Hc(T)和k推得,比较YBa2Cu3O7-δ的热力学参数,讨论了Pr离子的效应  相似文献   

2.
在两个简化结构模型的基础上,应用NORVIB程序对Ho(TTA)32H2O分子在1650~100cm-1波数范围的振动频率作了指认。在简正频率的计算值与实验值拟合优化后,确定了伸缩、弯曲、面外摇动和扭动等21个力常数以及9个相互作用力常数。计算值与实验值之间的平均偏差为4.75cm-1。  相似文献   

3.
本文用IOS方法和我们改进的Buckingham势计算了H2O-Ar、H2O-CO2混合气体中H2O分子谱线在高温下(600K、900K、1200K、1500K)的压力展宽半宽度。分析了谱线半宽度随温度变化的规律,同时也讨论了半宽度和被加宽分子大小的关系。  相似文献   

4.
液态低沸点气体的表面张力   总被引:1,自引:0,他引:1  
利用双毛细管法测定了液氮沸点温度下液氮的表面张力。用非线性方程γ=γ°(1-T/Tc)^n描述了液态N2、O2、ArXe、H2、Ne、He、Fe和Kr的表面张力与温度的关系,并采用一元性回归的方法拟合了上述各流体的参数γ°和n,准确度高于文献值,说明方程能正确表达表面张力与温度的关系。这些数据有利于对上述低沸点气体进行准确的热力学计算。  相似文献   

5.
在两个简化结构模型的基础上,应用NORVIB程序对Ho(TTA)32H2O分子在1650-100cm^-1波数范围的振动频率作了指认。在简正频率的计算值与实验值拟合优化后,确定了伸缩,弯曲,而外摇动和扭动等21个力常数以及9个相互作用力常数。  相似文献   

6.
在活塞圆筒式P~V关系测量装置上,研究了KH_2PO_4(KDP)和(CH_3NHCH_2CO-OH)_3CaCI_2[Tris-sarcosinecalciumchloride(TSCC)]在室温下、4.5GPa内的p~V关系。实验结果表明:KDP在2.1GPa左右有一个相变;TSCC在0.8GPa和3.2GPa左右各有一个相变。本工作还给出了它们在相变前后的状态方程,以及它们的格临爱森参数γO、体积模量B_o和B_o的压力导数B_o。  相似文献   

7.
利用北京谱仪在北京正负电子对撞机上采集的350万(2S)事例,通过(2S)→γπ-和γK+K-反应道测量了Xc0的总宽度.由MonteCarlo模拟给出的质量分辨函数,利用拟合Xc2谱形得到的质量分辨作标定后,用于Xc0宽度的拟合,得到Xc0的宽度为(15.0)MeV.同时定出了XcJ(J=0,2)到π+π=和K+K-的衰变分支比.结果为B(Xc0→π+π-)=(4.27±0.23±O.60)×10-3;B(Xc0→K+K-)=(3.44±0.21±0.47×10-3;B(Xc2→π+π-)=(1.52±0.17±0.29)×10-3和B(Xc2→K+K-)=(5.2±1.1±1.8)×10-4,其中第一项误差为统计误差,第二项为系统误差。  相似文献   

8.
激光沉积法制备(Y1—xHox)Ba2Cu3O7—δ薄膜   总被引:1,自引:1,他引:0  
本文报道了用激光沉积法在(100)LaAlO3衬底上制备(Y1-xHox)Ba2Cu3O7-δ(x=0,0.2,0.4)超导薄膜.结果表明,新超导薄膜表面光滑,具有很强的c轴织构,零电阻温度Tc0约91K,最佳临界电流密度Jc为4.7×106A/cm2(77K).  相似文献   

9.
阐述了全拟合分析方法的理论基础,通过对H280Se分子24个已知转动结构振动带的3516个上态能级的全拟合分析,得到112个基本光谱参数,拟合偏差为10.6×10-3cm-1。用这套基本光谱参数精确预言了首次记录的H280Se分子(500,A1)和(401,B2)局域模振动带的转动结构,并在简正模和局域模下分别拟合得到有效振转光谱参数。将归属得到的H280Se分子(500,A1)和(401,B2)振动带的252个上态能级并入全拟合中,得到114个基本光谱参数,拟合偏差为9.62×10-3cm-1。  相似文献   

10.
本文用IOS方法和我们改进的Buckingham势计算了H2O—Ar、H2O—CO2混合气体中H2O分子谱线在高温下(600K、900K、1200K、1500K)的压力展宽半宽度。分析了谱线半宽度随温度变化的规律,同时也讨论了半宽度和被加宽分子大小的关系。  相似文献   

11.
Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.  相似文献   

12.
A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.  相似文献   

13.
A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.  相似文献   

14.
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.  相似文献   

15.
The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results.  相似文献   

16.
The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.  相似文献   

17.
18.
With a novel light-weight and absolutely calibrated ultraviolet (UV) spectrometer, UV skylight radiances and O3 slant column densities are measured by balloon-borne limb measurements in Xinjiang area, China. UV skylight radiances measured at the height of 31 km are compared with the results from Modtran in the wavelength range from 290 to 420 nm. O3 slant column densities are derived from radiance spectra in the Huggins bands (320 - 335 nm) using differential optical absorption spectroscopy method. And the parameter exhibits a good correlation with the same value simulated by radiative transfer model (Tracy). The O3 profile simultaneously measured by an O3 sonde is used as input in Tracy calculations. The O3 sonde is launched on the same balloon.  相似文献   

19.
For breaking through the sensitivity limitation of conventional surface plasmon resonance (SPR) biosensors, novel highly sensitive SPR biosensors with Au nanoparticles and nanogratings enhancement have been proposed recently.But in practice, these structures have obvious disadvantages.In this study, a nanohole based sensitivity enhancement SPR biosensor is proposed and the influence of different structural parameters on the performance is investigated by using rigorous coupled wave analysis (RCWA).Electromagnetic field distributions around the nanohole are also given out to directly explain the performance difference for various structural parameters.The results indicate that significant sensitivity increase is associated with localized surface plasmons (LSPs) excitation mediated by nanoholes.Except to outcome the weakness of other LSP based biosensors, larger resonance angle shift, reflectance amplitude, and sharper SPR curves' width are obtained simultaneously under optimized structural parameters.  相似文献   

20.
Novel polymer distributed feedback(DFB)gratings are fabricated based on photopolymerization to reduce lasing threshold of polymer lasers.A photopolymer formulation sensitive to 355-nm ultraviolet(UV)light is proposed for the fabrication of polymer gratings and it can be used to form polymer films by spin-coating process.A very low surface-relief depth ranging from 12.5 to about 1.0 nm has been demonstrated with a refractive-index modulation of about 0.012.The experimental results indicate that such polymer gratings have promising potentials for the fabrication of low-order DFB organic semiconductor lasers.  相似文献   

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