HFC-143a和HFC-236fa饱和蒸气压的实验研究

改进了Burnett法PVTx性质实验台,温度和压力测量的最大不确定度分别为±10 mK和±400 Pa。精确测量了50组HFC-143a的饱和蒸气压实验数据,提出了一个5项的HFC-143a饱和蒸气压方程,适用于161.34 K到临界温度。与文献数据比较表明,改进后的实验台精度令人满意。测量了77组HFC-236fa的饱和蒸气压实验数据,温度范围为253-396 K,压力范围为44-3064 kPa。根据本文实验结果,拟合得到了一个Wagner型饱和蒸气压方程,与文献数据进行了比较,计算得到了HFC-236fa的正常沸点和偏心因子值。     

HFC-134a的表面张力试验研究

一、前言 HFC-134a目前被认为是CFC-12较为理想的替代物。迄今为止,国外正式发表的HFC-134a的表面张力数据及相应的关联式只有美国NIST的Chae等以及日本庆应大学的Okada等两份材料。表1汇集了这些情况。我们最近采用毛细管法,也初步测取了HFC-134a的表面张力数据。本文将详细介绍作者自行研制的装置和测试结果,并给出了表面张力随温度变化的关联式。     

一个HFC-134a的专用状态方程

一、问题的提出 HFC-134a是CFC-12的一种很有希望的替代物,对它的热力性质进行深入的研究非常必要,特别是状态方程的研究尤为重要,它是热力学参数计算的重要基础与依据。 评价一个状态方程的好坏,在于它的适用范围、再现不同相区PVT及导出量的精度以及使用的方便性。近几年国内外陆续发表了一些HFC-134a状态方程,其中主要包括日本的C.C.Piao等,美国的D.P.Wilson等,以及哈工大赵鸿斌等发表的方程。这     

适用于整个区域的HFC-227ea状态方程

基于现有的pvT和导出性质实验数据,拟合了一个HFC-227ea的35项专用状态方程。本方程适用于HFC-227ea压力从零至65MPa,密度从零至1730 kg.m_-3,温度从204至423 K整个流体区域的热力学性质计算。通过与实验结果比较,检验了对HFC-227ea各种热力学性质的计算精度,包括pvT性质、比定压热容、声速、焦汤系数、饱和蒸气压等,结果表明本方程具有很高的精度。     

Atomic force microscopy studies of SrTiO_3 (001) substrates treated by chemical etching and annealing in oxygen

~~Atomic force microscopy studies of SrTiO_3 (001) substrates treated by chemical etching and annealing in oxygen1. Koster, G, Rijnders, G, Blank, D. H. A. et al., Surface morphology determined by (001) single-crystal SrTiO3 termination, Physica C, 2000, 339: 215-230. 2. Kawasaki, M., Ohtomo, A., Arakane, T. et al., Atomic control of SrTiO3 surface for perfect epitaxy of per-voskite oxides, Appl. Surf. Sci., 1996,107: 102-106. 3. Kawasaki, M., Takahashi, K., Maeda, T. et a…     

Scale-free Networks with Self-Similarity Degree Exponents

Ravasz et al. structured a deterministic model of a geometrically growing network to describe metabolic networks. Inspired by the model of Ravasz et al., a random model of a geometrically growing network is proposed. It is a model of copying nodes continuously and can better describe metabolic networks than the model of Ravasz et al. Analysis shows that the analytic method based on uniform distributions （i.e., Barabási-Albert method） is not suitable for the analysis of the model and the simulation process is beyond computing power owing to its geometric growth mechanism. The model can be better analyzed by the Poisson process. Results show that the model is scale-free with a self-similarity degree exponent, which is dependent on the common ratio of the growth process and similar to that of fractal networks.     

Implementation of a multiple round quantum dense coding using nuclear magnetic resonance

~~Implementation of a multiple round quantum dense coding using nuclear magnetic resonance1. Bennett, C. H., Wiesner, S. J., Communication via one- and two-particle operators on Einstein-Podolsky-Rosen states, Phys. Rev. Lett., 1992, 69(20): 2881-2884. 2. Mattle, K., Weinfurter, H., Kwiat, P. G. et al., Dense coding in experimental quantum communication, Phys. Rev. Lett., 1996, 76(25): 4656-4659. 3. Fang, X. M., Zhu, X. W., Feng, M. et al., Experimental implementation of dens…     

混合制冷剂HFC-134a+HFC-152a液相黏度实验研究

寻找替代制冷剂的过程需要对制冷剂的物性有充分的了解,黏度是最重要的物性之一。本文使用一种将翻转法升液和压力容器承压相结合的黏度测量实验装置,对混合制冷剂HFC-134a+HFC-152a(摩尔比为0.29:0.71)进行液相黏度测量实验研究,测量了278.15～333.15 K温度范围内的液相黏度数据。为了方便工程运用,采用四种形式的Andrade方程对实验数据进行拟合,其中三种仅表征温度与黏度的关系,其余一种同时考虑了温度和压力对黏度影响。结果表明,由后者所得的关联式精度最高,平均绝对误差(AAD)和最大绝对误差(MAD)分别为0.495%和1.050%。此外,仅考虑温度的影响时,在Andrade方程中加入非线性修正对关联式的精度影响不大。     

Improved empirical formula for α particle preformation factor

In this contribution,the α preformation factors of 606 nuclei are extracted within the framework of the generalized liquid drop model(GLDM).Through the systematic analysis of the α preformation factors of even-even Po-U isotopes,we found that there is a significant weakening of influence of N=126 shell closure in uranium,which is consistent with the results of a recent experiment [J.Khuyagbaatar et al.,Phys.Rev.Lett.115,242502(2015)],implying that N=126 may not be the magic number for U isotopes.Furthermore,we propose an improved formula with only 7 parameters to calculate α preformation factors suitable for all types of α-decay;it has fewer parameters than the original formula proposed by Zhang et al.[H.F.Zhang et al.,Phys.Rev.C 80,057301(2009)]with higher precision.The standard deviation of the α preformation factors calculated by our formula with extracted values for all 606 nuclei is 0.365 with a factor of 2.3,indicating that our improved formula can accurately reproduce the α preformation factors.Encouraged by this,the α-decay half-lives of actinide elements are predicted,which could be useful in future experiments.Notably,the predicted α-decay half-lives of two new isotopes 220 Np [Z.Y.Zhang,et al.,Phys.Rev.Lett.122,192503(2019)] and 219 Np [H.B.Yang et al.,Phys.Lett.B 777,212(2018)] are in good agreement with the experimental α-decay half-lives.     

最近物理学综述评论文献题录

86-133.酶的13C核磁共振,(J·P·G·Malthouse), Progr.NMR Spectr.,18(1986),Pt.1,1- 59,参 205.86-133.利用核磁共振作流体的测量和成象.(j. Stepisnik),Progr.NMR Spectr.,18(1986), Pt.2,187—209,参 48.86-134.液晶聚合物的多脉冲动态核磁共振,(K· Muller et al.),Progr.     

Considering Backward Effect in Coupled Map Car-Following Model

Based on the pioneer work of Konishi et al., a new control method is proposed to suppress the traffic congestion in the coupled map （CM） car-following model under open boundary condition. The influence of the following car to the system has been considered. Our method and that presented by Konishi et al. [Phys. Rev. E 60 （1999） 4000] are compared. Although both the methods could suppress the traffic jam, the simulation results show that the temporal behavior obtained by ours is better than that proposed by the Konishi＇s et al. The simulation results are consistent with the theoretical analysis.     

A harmonious unifying hybrid preferential model and its universal properties for complex dynamical networks

To describe the real world which is a harmonious unification world with both de- terminism and randomness, we propose a harmonious unifying hybrid preferential model (HUHPM) of a certain class of complex dynamical networks. HUHPM is gov- erned only by the total hybrid ratio d/r according to the practical need. As some typical examples, the concepts and methods of the HUHPM are applied to the un-weighted BA model proposed by Barabási et al., the weighted BBV model pro- posed by Barat et al. and the weighted TDE model proposed by Wang et al. to get the so-called HUHPM-BA network, HUHPM-BBV network and HUHPM-TDE network. These HUHPM networks are investigated both analytically and numerically. It is found that the HUHPM reveals several universal properties, which more approach to the real-world networks for both un-weighted and weighted networks and have potential for applications.     

新的HFC134a蒸气压方程

一、引言 CFCs物质对大气臭氧层的破坏作用已引起世界范围的关注,使得开发研究新的、无污染的CFCs物质的替代物逐渐成为一个十分紧迫的问题。在众多可能的替代物中HFCl34a被认为是最有可能代替R_(12)的理想工质。 HFCl34a开发研究的历史不长,因此关于它蒸气压方程的文献并不是很丰富。表l列出了最近二、三年间发表的四个HFCl34a蒸气压方程的一些情况。由表l可以看出,     

制冷剂替代物相平衡性质的分子动力学模拟

本文利用分子动力学模拟算法研究制冷剂替代物的气液相平衡性质。通过将制冷剂替代物作为极性的2CLJ流体处理,建立了针对它们的 2CLJD 势能模型。利用 NPT+Test Particle 算法对五种制冷剂替代物 (HFC-152a,HFC-143a,HFC-134a,HCFC-142b和HFC-227ea)的气液相平衡性质进行了计算,同时验证了计算结果的热力学一致性。模拟结果与 NIST 的 REFPROP 数据库的最大相对偏差在2％以内。     

最近物理学综述评论性文献题录

90-191.二维相变.(A.G.Naumovets).Contemp. Phys.,30(1989),No.3,187—201·参约50.90-192.分支聚合物在胶凝阈值附近的逾渗长大 (M.Adam et al.).Contemp.Phys.,30(1989), No.3,203-218.参 17.90-193.超重元素的产生.(P.Ambruster et al.). Sci.Amer.,260(1989),No.5,36—42.参5.90-194.医学中的光学纤维.(A.Katzir).Sci. Amer.,260(1989),No.5,86-91.参4.90-195.Fourier变换.(R.N.Bracewell).Sci. Amer.,260(1989),No.6,62—69.参 4.90-196.电子和正电子的沟道效应.(A.H,S ren- sen　et al.).Sci.Amer.,260(1989),No.6,70-…     

最近物理学综述评论文献题录

88-355.金属表面的碱金属作用的分子吸附.(H.P. Bonzel).Surface Sci.Reports,8(1988),No.2,43- 125.参 172.88-356.聚乙炔中的孤[立] 子.(S.Roth et al.). Adv.phys.,36(1987),No.4,385-462.参147.88-357.固体内聚能理论.(G.P.Srivastava et al.). Adv.Phys.,36(1987),No.4,463—517.参约130.88-358.晶体的无公度性.(T.Janssen et al.).Adv Phys,36(1987),No.5,519—624.参约180.88-359.沉积岩的微几何形态和输运性质.(A.H. Thompson et al.). Adv.Phys,36(1987),No.5, 625—694.参约110.88-360.无序介质中的扩散.(S.Havlin et…     

Rapid growth of ternary eutectic under high undercooling conditions

~~Rapid growth of ternary eutectic un der high undercooling conditions1.Offerman, S.E., Dijk, N.H., Sietsma, J.et al., Grain nucleation and growth during phase transformations, Science, 2002, 298: 1003-1005. 2.Warren, J.A., Langer, J.S., Prediction of dendritic spacings in a directional-solidification experiment, Phys.Rev.E, 1993, 47: 2702-2712. 3.Cao, C.D., Wang, N., Wei, B., Containerless rapid solidification of undercooled Cu-Co peritectic alloys, Science in China, Ser.A, …     

Entanglement concentration for a non-maximally entangled four-photon cluster state

We present a scheme for locally concentrating a non-maximally entangled four-photon cluster state into a maximally-entangled four-photon cluster state. This scheme has a high success probability. The controlled-NOT （CNOT） gate is a crucial ingredient in this scheme, and we use a nearly deterministic CNOT gate, which is similar with that first introduced by Nemoto et al. （Phgs. Rev. Lett., 2004, 93： 250502）. This CNOT gate has a simple structure and does not need the strong nonlinearity.     

Quantum Teleportation and Superdense Coding via W-Class States

Abstract According to the protocol of Agrawal et al., we propose a cavity QED scheme for realization of teleportation and dense coding. Instead of using EPR states and GHZ states, our scheme is more insensitive to the loss of one particle by using a W-class state as a quantum channel. Besides, our scheme is immune to thermal field, and does not require the cavity to remain in the vacuum state throughout the procedure.     

Neutralization and Detachment in H^＋-H^- Collisions

The cross sections for neutralization and detachment in H^＋-H^- collisions in the energy range from 1.0 to lOO keV/u are calculated using the two-centre atomic orbital close-coupling （TC-AOCC） method. The results are compared with the available experimental and theoretical data. It is found that the neutralization cross section agrees well with the experimental data by Schon et al. [3. Phys. B 20 （1987） L759] and Melchert et al., [J. Phys. B 32 （1999） L139] especially at low energies. However, for the detachment process, our calculated cross section lies between the experimental data by Melchert et al. and by Peart et al. [J. Phys. B 9 （1976） 3047] for the energy below 15keV/u. Above this energy, our result is smaller than the two experimental data. It is worth pointing out that there exists a large difference between these two experimental data and it is difficult to judge which data is more accurate. Therefore, a high-precision measurement for detachment cross sections is expected to resolve this discrepancy and to test the theoretical calculations.