The Spectrum of a Binding System for a Heavy Quark with an Anti-Sbottom or for a Sbottom and Anti-Sbottom Pair

Since long-lived light bottom squark (sbottom) and its anti-particle with a mass close to the bottom quark have not been excluded by experiments so far, we consider such a sbottom to combine with its anti-particle to form a color singlet meson-like bound state or to combine with a common anti-quark to form a fermion-like one, or accordingly their anti-particles to form an anti-particle bound system. Namely we calculate the low-lying spectrum of the systems based on QCD inspired potential model. To be as relativistic as possible, we start with the framework of Bethe-Salpeter (BS) equation even for non-relativistic binding systems. Finally, we obtain the requested spectrum by constructing general forms of the BS wave functions and solving the BS equations under instantaneous approximation.Comment: 13 pages, 1 figur

Migration and emission of mercury from circulating fluidized bed boilers co-firing petroleum coke and coal

The migration and emission of mercury (Hg) were studied for three 410 t/h circulating fluidized bed (CFB) boilers co-firing petroleum coke and coal. Both the Ontario Hydro Method (OHM) and US Environmental Protection Agency (EPA) Method 30B were employed to sample gas phase emissions of mercury from the flue gas, and to compare the agreement for these different measurement methods in industrial application. Concurrent with flue gas sampling, solid and liquid samples including fuel, bottom ash, fly ash and gypsum, wastewater, etc., were also collected to determine the total mass balance and map the mercury migration from the power plant. The results showed that the mass balance rates ranged from 83.9% to 122.7%, which can be considered to be both acceptable and reliable. The vast majority of mercury emitted was distributed in the fly ash and stack gas, accounting for 61.36–67.71% and 22.22–33.35%, respectively. The total Hg concentration measured by OHM is comparable with that determined by EPA Method 30B; however, EPA Method 30B possesses advantages in terms of flexibility. The fabric filter (FF) has better Hg0 and Hg2+ removal efficiencies than the electrostatic precipitator (ESP). Because the Hg contained in the liquid waste streams greatly exceeded Chinese regulations, the main emphasis of future work should be focused on wastewater treatment. The mercury emission factors in this study are in the range of 0.69 g/TJ-0.80 g/TJ, which provides basic data for such CFB power plants in China. The CFB boilers equipped with ESP + WFGD or FF + WFGD appear to have the potential to significantly reduce Hg emission to the atmosphere

Partitioning behavior of Arsenic in circulating fluidized bed boilers co-firing petroleum coke and coal

The emission of Arsenic from coal-fired power plants has generated widespread environmental and human health concerns. This paper discusses Arsenic partitioning from three 440 t/h circulating fluidized bed (CFB) boilers co-firing petroleum coke and coal. All the boilers were equipped with electrostatic precipitator (ESP) or fabric filter (FF), and wet flue gas desulfurization (WFGD). Flue gas was sampled simultaneously both up- and down-stream of the ESP/FF and at the outlet of the WFGD based on EPA Method 29. Concurrent with flue gas sampling, feed fuel, bottom ash, ESP/FF ash, WFGD gypsum, WFGD wastewater, limestone slurry and flush water were also collected. The results show that, for three tested CFB boilers, the overall mass balance ratios of As ranged from 80.0%–114.2%, which can be considered to be acceptable and reliable. Most of the As was distributed in the bottom ash and ESP/FF ash with the values of 17.4%–37.5% and 55.6%–77.5%, respectively. Speciation analysis suggests that As5 + was the major water-soluble species in the feed fuel, bottom ash and fly ash, while As3 + was found to be the dominant species in WFGD wastewater. For three CFB boilers, the concentrations of total As in the stack emission were 0.97, 0.32 and 0.31 μg/m3, respectively. The CFB boiler equipped with ESP/FF + WFGD was shown to be able to provide good control of the emission of As emitted into the atmosphere

Partitioning behavior of Arsenic in circulating fluidized bed boilers co-firing petroleum coke and coal

The emission of Arsenic from coal-fired power plants has generated widespread environmental and human health concerns. This paper discusses Arsenic partitioning from three 440 t/h circulating fluidized bed (CFB) boilers co-firing petroleum coke and coal. All the boilers were equipped with electrostatic precipitator (ESP) or fabric filter (FF), and wet flue gas desulfurization (WFGD). Flue gas was sampled simultaneously both up- and down-stream of the ESP/FF and at the outlet of the WFGD based on EPA Method 29. Concurrent with flue gas sampling, feed fuel, bottom ash, ESP/FF ash, WFGD gypsum, WFGD wastewater, limestone slurry and flush water were also collected. The results show that, for three tested CFB boilers, the overall mass balance ratios of As ranged from 80.0%–114.2%, which can be considered to be acceptable and reliable. Most of the As was distributed in the bottom ash and ESP/FF ash with the values of 17.4%–37.5% and 55.6%–77.5%, respectively. Speciation analysis suggests that As5 + was the major water-soluble species in the feed fuel, bottom ash and fly ash, while As3 + was found to be the dominant species in WFGD wastewater. For three CFB boilers, the concentrations of total As in the stack emission were 0.97, 0.32 and 0.31 μg/m3, respectively. The CFB boiler equipped with ESP/FF + WFGD was shown to be able to provide good control of the emission of As emitted into the atmosphere

Colorectal cancer screening with fecal occult blood test: A 22-year cohort study.

The aim of the present study was to investigate the efficacy of colorectal cancer (CRC) screening with a three-tier fecal occult blood test (FOBT) in the Chinese population. The study was performed between 1987 and 2008 at the Beijing Military General Hospital, in a cohort of army service males and females aged >50 years. Between 1987 and 2005, a three-tier screening program, comprising guaiac-based FOBTs (gFOBTs), followed by immunochemical FOBTs for positive guaiac test samples and then colonoscopy for positive immunochemical test subjects, was performed annually. The cohort was followed up until 2008. The cohort included 5,104 subjects, of which, 3,863 subjects participated in screening (screening group) and 1,241 did not (non-screening group). The two groups did not differ in age, gender or other major risk factors for colon cancer. Overall, 36 CRCs occurred in the screening group and 21 in the non-screening group. Compared with the non-screening group, the relative risk for the incidence and mortality of CRC was 0.51 [95% confidence interval (CI), 0.30-0.87] and 0.36 (95% CI, 0.18-0.71), respectively, in the screening group. The general sensitivity of this three-tier FOBT was 80.6% (95% CI, 65.3-91.1). Thus, annual screening using the three-tier FOBT program may reduce the CRC incidence and mortality rate

The activated scaling behavior of quantum Griffiths singularity in two-dimensional superconductors

Quantum Griffiths singularity is characterized by the divergence of the dynamical critical exponent with the activated scaling law and has been widely observed in various two-dimensional superconductors. Recently, the direct activated scaling analysis with the irrelevant correction has been proposed and successfully used to analyze the experimental data of crystalline PdTe2 and polycrystalline \b{eta}-W films, which provides new evidence of quantum Griffiths singularity. Here we show that the direct activated scaling analysis is applicable to the experimental data in different superconducting films, including tri-layer Ga films and LaAlO3/SrTiO3 interface superconductor. When taking the irrelevant correction into account, we calculate the corrected sheet resistance at ultralow temperatures. The scaling behavior of the corrected resistance in a comparably large temperature regime and the theoretical fitting of the phase boundary give unambiguous evidence of quantum Griffiths singularity. Compared to the previous method based on the finite size scaling, the direct activated scaling analysis represents a more direct and precise way to analyze the experimental data of quantum Griffiths singularity in diverse two-dimensional superconductors

Soft Nonfactorizable Contribution to \bar{B}^0 \to D^0\pi^0

For the color-suppressed $\bar{B}^0\longrightarrow D^{0}\pi^{0}$ decay, nonfactorizable contributions are expected to be leading and naive factorization description breaks down. We estimate $1/m_b$ power-suppressed nonfactorizable effect in $\bar{B}^0\longrightarrow D^{0}\pi^{0}$, which is due to soft exchange between the emitted heavy-light quark pair and $B\pi$ system, in the framework of QCD light-cone sum rules (LCSR). The resulting correction to the decay amplitude is found to be numerically comparable with the corresponding factorizable piece, estimated at about $(50-110)$ of the latter. The relevant parameter $a_2$ receives a positive number contribution, due to the factorizable correction and the power-suppressed soft effect. Our findings would be crucial to phenomenological understanding of the $\bar{B}^0\longrightarrow D^{0}\pi^{0}$ decay.Comment: 15 pages, revtex, accepted for publication in EPJ