SO(5) Superconductors in a Zeeman Magnetic Field

The generic symmetry of a system under a uniform Zeeman magnetic field is U(1) x U(1). However, we show that SO(5) models in the presence of a finite chemical potential and a finite Zeeman magnetic field can have a exact SU(2) x U(1) symmetry. This principle can be used to test SO(5) symmetry at any doping level

Humanizing E-Mail Processing for Personal Information Management with Semantic Web and Speech Act Theory

With the rapid progress of information technology, Internet and people’s lives are combining closely with versatile communication ways now. Among these ways, the most popular one for knowledge workers is e-mail. People use it to deal with business affairs or receiving information in daily life. That gradually induces every knowledge worker has to handle many grueling e-mails every day. As a result, knowledge workers may be stuck most of their time with the e-mail distention problem. Although there are growing e-mail management systems, most of them are still short of freeing user to set, reply or retrieve related information with customized personal dexterity. That is, the data or information in the e-mail system is still obstinate for most of the knowledge workers. To mitigate this problem, we rethink the spirit of an e-mail system from the perspectives of speech act theory, and use the six ethics of heart to construct the kernel of the social network with data provenance to help users reduce the gap between current e-mail routine process and their own personal information management. Together with the customized Semantic Web construction, our approach hopefully helps knowledge workers establish a more efficient e-mail processing model with humanity consideration

Dynamic modeling and tracking control of a nonholonomic wheeled mobile manipulator with dual arms

This paper presents methodologies for dynamic modeling and trajectory tracking of a nonholonomic wheeled mobile manipulator (WMM) with dual arms. The complete dynamic model of such a manipulator is easily established using the Lagrange's equation and MATHEMATICA. The structural properties of the overall system along with its subsystems are also well investigated and then exploited in further controller synthesis. The derived model is shown valid by reducing it to agree well with the mobile platform model. In order to solve the path tracking control problem of the wheeled mobile manipulator, a novel kinematic control scheme is proposed to deal with the nonholonomic constraints. With the backstepping technique and the filtered-error method, the nonlinear tracking control laws for the mobile manipulator system are constructed based on the Lyapunov stability theory. The proposed control scheme not only achieves simultaneous trajectory and velocity tracking, but also compensates for the dynamic interactions caused by the motions of the mobile platform and the two onboard manipulators. Simulation results are performed to illustrate the efficacy of the proposed control strategy

The Simplest Little Higgs

We show that the SU(3) little Higgs model has a region of parameter space in which electroweak symmetry breaking is natural and in which corrections to precision electroweak observables are sufficiently small. The model is anomaly free, generates a Higgs mass near 150 GeV, and predicts new gauge bosons and fermions at 1 TeV.Comment: 13 pages + appendix, typos corrected, version to appear in JHE

Seasonal variation and spatial distribution of carbonaceous aerosols in Taiwan

To investigate the physico-chemical properties of aerosols in Taiwan, an observation network was initiated in 2003. In this work, the measurements of the mass concentration and carbonaceous composition of PM(10) and PM(2.5) are presented. Analysis on the data collected in the first 5-years, from 2003 to 2007, showed that there was a very strong contrast in the aerosol concentration and composition between the rural and the urban/suburban stations. The five-year means of EC at the respective stations ranged from 0.9 +/- 0.04 to 4.2 +/- 0.1 mu gC m(-3). In rural areas, EC accounted for 2-3% of PM(10) and 3-5% of PM(2.5) mass loadings, comparing to 4-6% of PM(10) and 4-8% of PM(2.5) in the urban areas. It was found that the spatial distribution of EC was consistent with CO and NO(x) across the network stations, suggesting that the levels of EC over Taiwan were dominated by local sources. The measured OC was split into POC and SOC counterparts following the EC tracer method. Five-year means of POC ranged from 1.8 +/- 0.1 to 9.7 +/- 0.2 mu gC m(-3) among the stations. It was estimated that the POM contributed 5-17% of PM(10) and 7-18% of PM(2.5) in Taiwan. On the other hand, the five-year means of SOC ranged from 1.5 +/- 0.1 to 3.8 +/- 0.3 mu gC m(-3). The mass fractions of SOM were estimated to be 9-19% in PM(10) and 14-22% in PM(2.5). The results showed that the SOC did not exhibit significant urban-rural contrast as did the POC and EC. A significant cross-station correlation between SOC and total oxidant was observed, which means the spatial distribution of SOC in Taiwan was dominated by the oxidant mixing ratio. Besides, correlation was also found between SOC and particulate nitrate, implying that the precursors of SOA were mainly from local anthropogenic sources. In addition to the spatial distribution, the carbonaceous aerosols also exhibited distinct seasonality. In northern Taiwan, the concentrations of all the three carbonaceous components (EC, POC, and SOC) reached their respective minima in the fall season. POC and EC increased drastically in winter and peaked in spring, whereas the SOC was characterized by a bimodal pattern with the maximal concentration in winter and a second mode in summertime. In southern Taiwan, minimal levels of POC and EC occurred consistently in summer and the maxima were observed in winter, whereas the SOC peaked in summer and declined in wintertime. The discrepancies in the seasonality of carbonaceous aerosols between northern and southern Taiwan were most likely caused by the seasonal meteorological settings that dominated the dispersion of air pollutants. Moreover, it was inferred that the Asian pollution outbreaks could have shifted the seasonal maxima of air pollutants from winter to spring in the northern Taiwan, and that the increases in biogenic SOA precursors and the enhancement in SOA yield were responsible for the elevated SOC concentrations in summer

Radiative Corrections to One-Photon Decays of Hydrogenic Ions

Radiative corrections to the decay rate of n=2 states of hydrogenic ions are calculated. The transitions considered are the M1 decay of the 2s state to the ground state and the E1(M2) decays of the $2p_{1/2}$ and $2p_{3/2}$ states to the ground state. The radiative corrections start in order $\alpha (Z \alpha)^2$, but the method used sums all orders of $Z\alpha$. The leading $\alpha (Z\alpha)^2$ correction for the E1 decays is calculated and compared with the exact result. The extension of the calculational method to parity nonconserving transitions in neutral atoms is discussed.Comment: 22 pages, 2 figure

Geotextile behavior relevant to filtering low density suspended organic particles

Presented at the 8th International Geosynthetics Conference. Yokohama, Japan.This paper describes experiments on the feasibility of using geotextiles to filter organics from runoff and combined sewer overflows. A horizontal flow permittivity test apparatus was used as a prototype to test 15cm x 20cm coupons. Non-woven, needle-punched products supported both depth (interior) and cake(surface) filtration modes. Crushed anthracite in the #100-#200 mesh range was used as an inert, replicable analogue of low density, irregularly shaped suspended particles. The AOS detected with this material differs from that measured with standard media, indicating different interaction with the geotextile pore structure.Drag forces maintained a cake on the upstream face of the filter even at low hydraulic gradients. The permittivity decreased as this coating thickened. When flow ceased, the organic cake sloughed off the upstream face of the coupon. Measurements made after several doses showed recovery of much of the original permittivity, with the loss in hydraulic capacity attributed to embedment of particles in the matrix