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1.
吴宁  阮图南  郑志鹏 《中国物理》2001,10(7):611-612
After considering its mixing with the glueball, we give a new mass relation for the meson nonet. According to this mass relation and the predicted mass of the pseudoscalar glueball given by lattice calculations and the effective Hamiltonian, the expected mass of the mixed pseudoscalar glueball is about 1.7 GeV. This result is helpful in the experimental search for the mixed isoscalar pseudoscalar glueball. η(1760) is discussed as a possible candidate for this type of particle.  相似文献   

2.
We formulate a Hamiltonian theory on the lattice including next-to-nearest neighbor fermion interactions. A canonical transformation is made to induce a momentum-dependent mass term. The meson spectrum is studied by using this Hamiltonian. The current algebra formula for the pion mass is derived. The ρ-ω mass ratio in the intermediate coupling region is in agreement with the experimental value.  相似文献   

3.
We continually use the phenomenological of the galaxy with two constituents (v+B) as in a previous paper [1] and uniformly handle S galaxy, E galaxy, etc. through the normalization method. At the same time, we extend this model from degenerate condition to isoentropic condition and from low temperature to high temperature. Thus, on a much more perfect foundation it is indirectly verified that the massive neutrino can account for the missing mass hidden in different celestial scales between galaxy and galactic cluster, but it can not rule out the possibiilty that there are some new massive fermions which are lighter than neutrino. Besides, in this paper we handle 21 samples of Sc galaxy yet, and obtain the average upper limit (15 eV.) of mv. Because the spherically symmetric model is insufficient for calculation of mv, we will progres sively research the non-spherically symmetric model, in another paper.  相似文献   

4.
On the basis of the beaming model, we have derived a relation between the observed polarization (Pob) and Doppler-corrected optical magnitude (mcorr), log Pob=0.4(1-k) mcorr+C. We tested the correlation between Pob} and mcorr. The main results are as follows: (1) for both high and low states, there are strong correlations between Pob and mcorr for 29 RBLs with well-observed polarization and Doppler factor, where mcorr=mob+(3+α)logδ/0.4, and δ is the optical Doppler factor; (2) no correlation exists between Pob and the observed optical magnitude, mob, for the 29 RBLs in high state, but there is a close correlation for the 29 RBLs in low state; (3) however, there is an obvious anti-correlation between Pob and mcorr for 35 XBLs with good simultaneous observation data. Our results show that (i) a new difference in polarization is found between RBLs and XBLs; (ii) this difference in polarization between RBLs and XBLs seems really to be physical differences.  相似文献   

5.
干涉和衍射的联系与区别   总被引:1,自引:0,他引:1  
吕太国 《物理与工程》2010,20(1):19-20,25
通过理论分析得出双缝实验中空间光场的分布是干涉与衍射共同作用的结果.在形成条件、分布规律以及数学处理方法上说明了干涉和衍射的区别与联系.  相似文献   

6.
循环床中气固两相局部传热传质规律的研究   总被引:5,自引:0,他引:5  
本文对含湿颗粒在循环床中干燥过程的传热传质规律进行了实验研究。本文发展的一种利用双热电偶参考标定法,获得了气、固两相沿床高的局部温度。对气体表观流速,固体循环率,颗粒初始含湿量对传热传质的影响进行了分析和讨论。所获得的循环床中传热传质系数的实验关联式,可供干燥颗粒、造粒、粒面包裹等工业设计参考使用。  相似文献   

7.
热质的运动和传递-最低热质能耗散原理和热质运动方程   总被引:1,自引:0,他引:1  
过增元基于质能方程提出了热质的概念.在非平衡热力学中,存在最低能量耗散原理,根据该原理可以导出热传导,扩散及粘性流动等不可逆输运过程的方程式.当采用热质模型对传热现象进行描述时,发现热质的运动也满足最小作用量原理:最低热质能耗散原理,根据该原理可以推导得出热质运动的动量守恒方程。  相似文献   

8.
The observed quark mass hierarchy and the realistic mixing matrix of quark charged currents may be explained in a framework of a three-fermion composite model, if the quark masses are generated by the condensaties of exotic colored fermions and in the dynamical mechanism, we incorporate the following conjecture that the four-preon hypercolor condensates, which are used to realize the spontaneous breaking of the family gauge group suF(2) in the model, may correspond to two different mass scales. We also show that all the FCNC including the |ΔS|=2 effective coupling in the model can be suppressed down to below the experimental limit.  相似文献   

9.
何景棠 《物理学进展》2001,21(2):216-224
本介绍中微子质量测量的历史和现状。介绍太阳中微子丢失实验的结果和大气μ中微子丢失实验结果。这些结果表明存在中微子振荡,即中微子具有质量。它是超出标准模型的信号。本还介绍了21世纪初研究中微子振荡的若干重要实验,例如长基线中微子振荡实验以及建造μ子 贮存环来产生高能电子中微子束进行中微子振荡的实验以及测量中微子振荡时的CP破坏的设想。  相似文献   

10.
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12.
It is conjectured and shown by means of the screening Casimir effective couplings among fer-mions that,the four-fermivn condensates<(ff)2> formed through the SU(N).hypercolor gauge interac-tions,in geneial,may always have two forming paths which respectively correspond to different mass scales, and only for some special SU(N) representations of the fermions f the condensates have one mass scale or no four-fermion condensate could be formed.  相似文献   

13.
DMFC两相流及其对传质影响的研究   总被引:2,自引:0,他引:2  
采用自制的实验系统对液态进料直接甲醇燃料电池(DMFC)阳极交叉指状流道内的两相况功特性进行了可视化实验研究.自制的DMFC单电池带有透明窗口,采用镀金的不锈钢阴极极板和透明的聚碳酸脂阳极流场板,电解质为Nafion117膜.实验过程中燃料电池的进口总管和出口总管是水平的,进口流道和出口流道是竖直的.实验发现,出口流道中典型的两相流流型是泡状流、而出口总管中的典型流型是弹状流.进口流道中的气弹和气柱导致了阳极传质恶化.  相似文献   

14.
Atomicmassspectrometry,embodiedusualyasinductivelycoupledplasmamassspectrometry(ICPMS)orglowΑdischargemassspectrometry(GDMS),...  相似文献   

15.
The biodynamic apparent mass response characteristics of 24 human subjects (12 males and 12 females) seated under representative automotive postures with hands-in-lap (passengers) and hands-on-steering wheel (drivers) are reported. The measurements were carried out under white noise vertical excitations of 0·25, 0·5 and 1·0m/s2r.m.s. acceleration magnitudes in the 0·5-40Hz frequency range and a track measured input (1·07m/s2). The measured data have been analyzed to study the effects of hands position, body mass, magnitude and type of vibration excitation, and feet position, on the biodynamic response expressed in terms of apparent mass. A comparison of the measured response of subjects assuming typical automotive postures involving inclined cushion, inclined backrest and full use of backrest support with data determined under different postural conditions and excitation levels revealed considerable differences. The biodynamic response of automobile occupants seated with hands in lap, peaks in the 6·5-8·6Hz frequency range, which is considerably higher than the reported range of fundamental frequencies (4·5-5Hz) in most other studies involving different experimental conditions. The peak magnitude tends to decrease considerably for the driving posture with hands-on-steering wheel, while a second peak in the 8-12 Hz range becomes more apparent for this posture. The results suggest that biodynamic response of occupants seated in automotive seats and subject to vertical vibration need to be characterized, as a minimum, by two distinct functions for passenger and driving postures. A higher body mass, in general, yields higher peak magnitude response and lower corresponding frequency for both postures. The strong dependence of the response on the body mass is further demonstrated by grouping the measured data into four different mass ranges: less than 60 kg, between 60·5 and 70 kg, between 70·5 and 80 kg, and above 80 kg. From the results, it is concluded that hands position and body mass have the most significant influence on the apparent mass response under automotive posture and vibration.  相似文献   

16.
QUICK与多种差分方案的比较和计算   总被引:9,自引:3,他引:6  
本文用QUICK和多种差分方案计算了四个流动与换热问题.计算结果表明。对于强制流动问题,QUICK用较粗网格就能得到其他差分方案用较细网格才能得到的结果。对稳态自然对流,QUICK与其他差分方案的计算结果相近,但QUICK方案能预测出所计算的低Pr数流体自然对流的物理振荡,而其他几种方案不能.  相似文献   

17.
This paper extends an earlier study on sound propagation over poro-elastic layered ground to range-dependent and topographic ground. The model is based on a pressure-velocity finite-difference formulation and is coded in the computer program PORAC. To highlight the influence of range-dependent parameters and topographic features on sound propagation, four cases are considered: (i) a homogeneous poro-elastic half-space (the base case); (ii) the base case with a zone in the ground with a higher permeability; (iii) the base case with a zone of higher stiffness; (iv) the base case with a rectangular hill. The paper presents typical results of sound propagation in these cases comprising synthetic time histories of overpressure in the atmosphere and ground vibration as well as snapshots of the response of the atmosphere-ground system at selected times. Comparative results in these cases serve to highlight the effect of the various non-homogeneities considered in this study.  相似文献   

18.
An analysis for various components included in the difference of angular momentum between excited and ground bands, i(ω), is done carefully. It is pointed out that, generally, i(ω) should read as i(ω)=iRAL(ω)+iPR(ω)+iSC(ω). And the i(ω). corresponding to s-band of the first backbanding in even-even nuclei is really not only the iRAL(ω). The various components in i(ω) corresponding to s-band for three typical nuclei 164Er, 188Hg and 156Er are estimated quantitatively and microscopicly by using cranked shell model. For well deformed nuclei, iRAL plays the dominant role, but the contribution of pairing reduction, iPR, can not be neglected. As for the soft nuclei like 188Hg, the contribution from shape changes, iSC, is very important. While for transitional nuclei as 156Er, both pairing reduction and shape changes will play substantial role.  相似文献   

19.
质子交换膜燃料电流道淹没与传质强化   总被引:1,自引:0,他引:1  
在地面常重力环境下,采用透明电池可视化方法研究了质子交换膜燃料电池阳极和阴极的流道淹没现象。分别研究了阳极和阴极反应物流量对电池内部传质和电池性能的影响。结果表明,电池阴极的淹没区域比阳极大,由电极淹没引起的气体传质受限和电化学反应受限主要发生在阴极。提高反应物流量能够强化气体传质并提高电池性能,并且提高电池阴极侧反应物流量比提高阳极侧反应物流量对提高电池性能更有效。本文工作为进一步开展微重力环境中的燃料电池实验提供了比较依据。  相似文献   

20.
分形介质的传热与传质分析(综述)   总被引:9,自引:0,他引:9  
本文论述了分形介质的分形理论和数学基础,并简要综述了用分形理论和方法研究分形介质的传热与传质特性(如多孔介质的渗透率、热导率以及池核态沸腾换热)方面目前所取得的研究进展,最后扼要展望了用分形理论和方法进一步研究分形介质的传热与传质的可能的若干课题和方向。  相似文献   

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