Search for New Bottomlike Quark Pair Decays QQ̅ →(tW∓)(t̅ W±) in Same-Charge Dilepton Events

We report the most restrictive direct limits on masses of fourth-generation down-type quarks b′, and quarklike composite fermions (B or T5/3), decaying promptly to tW∓. We search for a significant excess of events with two same-charge leptons (e, μ), several hadronic jets, and missing transverse energy. An analysis of data from pp̅ collisions with an integrated luminosity of 2.7  fb-1 collected with the CDF II detector at Fermilab yields no evidence for such a signal, setting mass limits mb′, mB>338  GeV/c2 and mT5/3>365  GeV/c2 at 95% confidence level.

Search for New Bottomlike Quark Pair Decays QQ̅ →(tW∓)(t̅ W±) in Same-Charge Dilepton Events

We report the most restrictive direct limits on masses of fourth-generation down-type quarks $b^{\prime}$, and quark-like composite fermions ($B$ or $T_{5/3}$), decaying promptly to $t W^{\mp}$. We search for a significant excess of events with two same-charge leptons ($e$, $\mu$), several hadronic jets, and missing transverse energy. An analysis of data from $p\overline{p}$ collisions with an integrated luminosity of 2.7 fb$^{-1}$ collected with the CDF II detector at Fermilab yields no evidence for such a signal, setting mass limits $m_{b^{\prime}}, m_{B} >$ 338 $\mathrm{GeV}/c^2$ and $m_{T_{5/3}} >$ 365 $\mathrm{GeV}/c^2$ at 95% confidence level.

Compact 120 TW Ti: sapphire laser system with a high gain final amplifier

A 120TW/36fs laser system based on Ti:sapphire chirped-pulse amplification (CPA) has been successfully established in our lab. The final four pass Ti:sapphire amplifier pumped by an energetic single-shot Nd:YAG-Nd:glass laser was designed and optimized. With 24J/8ns pump energy at 532 nm, 300 mJ/220 ps chirped pulse was amplified to 5.98 J in this amplifier, and a total saturated gain of similar to 20 was achieved. The focused intensity of compressed beam could reach to 10(20) W/cm(2) with the M-2 of similar to 2.0. (c) 2005 Elsevier Ltd. All rights reserved.

High-energy ion emission from cooled deuterium clusters in 20 TW laser fields

High-energy ion emission from intense-ultrashort (30fs) laser-pulse- cooled deuterium-cluster (80K) interaction is measured. The deuterium ions have an average energy 20keV, which greatly exceeds Zweiback's expectation [Phys. Rev. Lett. 84 (2000) 2634]. These fast deuterium ions can be used to drive fusion and have a broad prospect.

Generation of 17-TW 23-fs pulses with a two-stage Ti : Sapphire amplifier at repetition rate 10 Hz

We have developed a two-stage Ti:sapphire amplifier system which can produce 17-TW/23-fs pulses at a repetition rate 10 MHz. A birefringent plate is used in the regenerative amplifier to alleviate gain narrowing, while an all-reflective cylindrical-mirror-based pulse stretcher and an acousto-optic programmable dispersive filter (AOPDF) are used to compensate for the higher order dispersion of the system.

TW-80对污染土壤中菲和芘的生物降解影响

以 Ｔ Ｗ８０ 为供试物，进行了表面活性剂对污染土壤中菲和芘生物降解影响研究． 实验周期１５０ ｄ ．并分别在３０ ｄ 、６０ ｄ 和１５０ ｄ 间隔采样监测菲、芘降解率．结果表明，３０ ｄ 后，加入 Ｔ Ｗ８０ 的不同处理土壤中，菲的降解率分别达８１ ％ ～９８ ．９ ％ ，比 Ｃ Ｋ 高２２ ．０２ ％ 以上、芘的降解率分别达７１ ．９０ ％ ～８０ ．６６ ％ ，比 Ｃ Ｋ 高９ ．４６ ％ 以上．６０ ｄ 后，加入 Ｔ Ｗ８０ 的处理中，菲的降解率达８８ ．９４ ％ ～９６ ．５１ ％ 、比 Ｃ Ｋ 高１１ ．１４ ％ 以上； 芘降解率达９２ ．３９ ％～９４ ．０２ ％ ，比 Ｃ Ｋ 高２ ．２７ ％ 以上．１５０ ｄ 后，所有处理中，菲和芘的降解率均分别达到９８ ％ 和９６ ％ 以上， 与 Ｃ Ｋ 无明显差别．研究还发现， Ｔ Ｗ８０ 土壤中含有优势真菌常见青霉、蠕形青霉、淡紫青霉和顶孢头孢霉．它们可能是促进土壤中菲、芘降解的原因

表面活性剂TW-80对土壤中多环芳烃生物降解的影响

以表面活性剂ＴＷ８０为供试物，进行了为期１５０ｄ的实验研究，并分别在３０、６０和１５０ｄ间隔采样监测ＰＡＨｓ降解率．结果表明，３０ｄ后，土壤中ＰＡＨｓ的降解率达９０％，比对照提高约３０％．６０ｄ后，浓度为１００００ｍｇ·ｋｇ－１表面活性剂的土壤和对照中，ＰＡＨｓ降解率从６５．１％和６０％迅速提高到９３．８％和７９．２％．其它处理中，ＰＡＨｓ的平均降解率仅比３０ｄ的结果提高４％．１５０ｄ后，所有处理中ＰＡＨｓ的降解率均达到９０％以上．可以认为，表面活性剂能提高ＰＡＨｓ的生物可利用性，加快ＰＡＨｓ的降解速率，从而减少污染暴露时间．但表面活性剂浓度过高可抑制微生物活性．研究还发现，ＴＷ８０土壤中含有优势真菌．经鉴定为常见青霉、蠕形青霉、淡紫青霉和顶孢头孢霉．它们是土壤ＰＡＨｓ迅速降解的动因

Imaging of high harmonic radiation emitted during the interaction of a 20 TW laser with a solid target

We present images of the source of extreme ultraviolet (XUV) harmonic emission at a wavelength of 220 Angstrom from the interaction of a 20 TW, 1.053 mu m Nd:glass laser beam focused to intensities up to 4x10(18) W cm(-2) onto a solid target. From these measurements we determine an upper limit to the source size and brightness of the harmonic emission to show its efficacy as a novel source of short-pulse, coherent XUV radiation. We also demonstrate the empirical scaling of the harmonic generation efficiency with irradiance up to 10(19) W mu m(2) cm(-2), and extrapolate to estimate the possible source brightness at higher irradiances. These source brightnesses are compared to those available from an x-ray laser system. (C) 1997 American Institute of Physics.

Guiding of a 10-TW picosecond laser pulse through hollow capillary tubes

Efficient guiding of 1-ps infrared laser pulses with power exceeding 10 TW has been demonstrated through hollow capillary tubes with 40- and 100-mu m internal diameters and lengths up to 10 mm, with transmission greater than 80% of the incident energy coupled into the capillary. The beam is guided via multiple reflections off a plasma formed on the walls of the guide by the pulse's rising edge, as inferred from optical probe measurements.

ALMA Observations of a Gap and a Ring in the Protoplanetary Disk around TW Hya

We report the first detection of a gap and a ring in dust continuum emission from the protoplanetary disk around TW Hya, using the Atacama Large Millimeter/Submillimeter Array. The gap and ring are located at 25 and 41 AU from the central star, respectively, and are associated with the CO snowline at ~ 30AU. The gap width and depth are 15AU at the maximum and 23% at the minimum, respectively, regarding that the observations are limited to an angular resolution of ~ 15AU. In addition, we detect a decrement in CO line emission down to ~ 10AU, indicating freeze-out of gas-phase CO onto grain surfaces and possible subsequent surface reactions to form larger molecules. According to theoretical studies, the gap could be caused by gravitational interaction between the disk gas and a planet with a mass less than super-Neptune (2 Neptune mass), or result from destruction of large dust aggregates due to the sintering of CO ice.

Trigonometric parallaxes in the TW Hydrae Association

We have conducted a program of trigonometric distance measurements to 13 members of the TW Hydrae Association (TWA), which will enable us (through back-tracking methods) to derive a convincing estimate of the age of the association, independent of stellar evolutionary models. With age, distance, and luminosity known for an ensemble of TWA stars and brown dwarfs, models of early stellar evolution (which are still uncertain for young ages and substellar masses) will then be constrained by observations over a wide range of masses (0.025 to 0.7 M⊙).

Avaliação do AAM - Active Appearance Model para detecção de regiões de interesse em radiografias carpais na estimativa da idade óssea através do método TW

In several areas of health professionals (pediatricians, nutritionists, orthopedists, endocrinologists, dentists, etc.) are used in the assessment of bone age to diagnose growth disorders in children. Through interviews with specialists in diagnostic imaging and research done in the literature, we identified the TW method - Tanner and Whitehouse as the most efficient. Even achieving better results than other methods, it is still not the most used, due to the complexity of their use. This work presents the possibility of automation of this method and therefore that its use more widespread. Also in this work, they are met two important steps in the evaluation of bone age, identification and classification of regions of interest. Even in the radiography in which the positioning of the hands were not suitable for TW method, the identification algorithm of the fingers showed good results. As the use AAM - Active Appearance Models showed good results in the identification of regions of interest even in radiographs with high contrast and brightness variation. It has been shown through appearance, good results in the classification of the epiphysis in their stages of development, being chosen the average epiphysis finger III (middle) to show the performance. The final results show an average percentage of 90% hit and misclassified, it was found that the error went away just one stage of the correct stage.