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991.
Abazov VM Abbott B Abolins M Acharya BS Adams M Adams T Agelou M Ahn SH Ahsan M Alexeev GD Alkhazov G Alton A Alverson G Alves GA Anastasoaie M Andeen T Anderson S Andrieu B Anzelc MS Arnoud Y Arov M Askew A Asman B Jesus AC Atramentov O Autermann C Avila C Ay C Badaud F Baden A Bagby L Baldin B Bandurin DV Banerjee P Banerjee S Barberis E Bargassa P Baringer P Barnes C Barreto J Bartlett JF Bassler U Bauer D Bean A Begalli M Begel M Belanger-Champagne C Bellantoni L Bellavance A Benitez JA 《Physical review letters》2006,97(16):161802
We present a search for a neutral particle, pair produced in pp[over] collisions at sqrt[s]=1.96 TeV, which decays into two muons and lives long enough to travel at least 5 cm before decaying. The analysis uses approximately 380 pb(-1) of data recorded with the D0 detector. The background is estimated to be about one event. No candidates are observed, and limits are set on the pair-production cross section times branching fraction into dimuons + X for such particles. For a mass of 10 GeV and lifetime of 4x10(-11) s, we exclude values greater than 0.14 pb (95% C.L.). These results are used to limit the interpretation of NuTeV's excess of dimuon events. 相似文献
992.
A highly sensitive method is proposed to determine copper(II) ions by forming a stable complex through their interaction with
4-(2′-benzothiazolylazo)-salicylic acid (BTAS) at room temperature and pH of about 5.0. The complex gave a maximum absorption
at λ = 485 nm with a molar absorptivity coefficient of 2.35·104 l/(mol·cm). The linear range for the copper determination is 0.63–5.04 mg/l. The method can be applied to determine copper
ions in different biological specimens like some drugs and water samples. 相似文献
993.
A. Sargsyan C. Leroy Y. Pashayan-Leroy R. Mirzoyan A. Papoyan D. Sarkisyan 《Applied physics. B, Lasers and optics》2011,105(4):767-774
The electromagnetically induced transparency (EIT) on the atomic D
1 line of rubidium is studied using a nanometric-thin cell with atomic vapor column length in the range of L=400–800 nm. It is shown that the reduction of the cell thickness by four orders as compared with an ordinary cm-size cell
still allows to form an EIT resonance for L=λ=794 nm with the contrast of up to 40%. Further reduction of thickness to L=λ/2 leads to significant reduction of EIT contrast, verifying that the key parameter for EIT in wavelength-scale-thickness
cells is not the value of L itself but L/λ ratio. Remarkable distinctions of EIT formation in nanometric-thin and ordinary cells are demonstrated. Well-resolved splitting
of the EIT resonance in a magnetic field for L=λ can be used for magnetometry with nanometric spatial resolution. The presented theoretical model well describes the observed
results. 相似文献
994.
A. Nakajima Y. Masuda E. Matsuda Y. Ueda H. Sameshima T. Ikenoue 《Applied magnetic resonance》2011,40(4):535-544
The reaction between 3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (PCAM), which is a blood–brain-barrier (BBB)
permeable stable cyclic nitroxide, and ascorbic acid was examined in a low dissolved oxygen-phosphate buffer (low DO-PB, 0.1 mM
DO) under 8% oxygen in a glove bag or in an ordinal dissolved oxygen-phosphate buffer (ordinal DO-PB, 0.3 mM DO) under 21%
oxygen in an open atmosphere with and without diethylenetriaminepentaacetic acid (DTPA). In PB with DTPA, no difference was
observed between the results in the low DO-PB and those in the ordinal DO-PB. In the ordinal DO-PB without DTPA, the rate
constant of the PCAM decrease was half that in the low DO-PB without DTPA. The present results indicate that high DO and coexisting
transition metal ions caused the oxidation of ascorbic acid, which degraded the PCAM reduction. The stable nitroxide-ascorbic
acid system without DTPA was found to be applicable to an in vitro model for the acute hypoxia ischemia. 相似文献
995.
A passively Q-switched 1.06 μm laser with Cr4+:YAG saturable absorber by direct 879 nm diode pumping grown-together composite GdVO4/Nd:GdVO4 crystal to the emitting level was demonstrated in this paper. The characteristics of pulsed laser were investigated by using
two kinds of Cr4+:YAG crystal with the initial transmissivity of 80 and 90%, respectively. When the T
0 = 90% Cr4+:YAG was used, an average output power of 1.59 W was achieved at an incident pump power of 10 W. The pulse width and repetition
rate were 64.5 ns and 170 kHz, respectively. The thermal lens effect of laser crystal was analyzed. 相似文献
996.
A Q-switched high efficient Ho:YAlO3 (Ho:YAP) laser pumped by a diode-pumped Tm:YLF laser at room-temperature is realized. The maximum output energy reaches 1.58
mJ under the repetition frequency of 5 kHz, when the incident pump power is 15.6 W. The pulse width is 22 ns. The wavelength
is 2118 nm when the transmission of output coupler is 30%. The beam quality factor is M
2 ∼ 1.39 measured by the traveling knife-edge method. 相似文献
997.
J.-H. Yuan X.-Z. Sang C.-X. Yu L. Rao Y. Han G.-Y. Zhou S.-G. Li L.-T. Hou 《Applied physics. B, Lasers and optics》2011,105(4):685-688
Using the photonic crystal fiber (PCF) with the zero dispersion wavelength of 848 nm for the fundamental mode, the efficient
anti-Stokes signal generations from 645 to 543 nm are realized by pumping in the normal dispersion region. When the pump average
power increases from 200 to 500 mW, the output power of the anti-Stokes signal increases 8.46 times, the power ratio of the
anti-Stokes signal at 543 nm to the residual pump is calculated as 22.6:1, and the conversion efficiency η in the experiment can be up to 46%. Moreover, good optical beam quality of the anti-Stokes signal can be achieved. 相似文献
998.
X. F. Yang D. Y. Shen T. Zhao H. Chen J. Zhou J. Li H. M. Kou Y. B. Pan 《Laser Physics》2011,21(6):1013-1016
We report on a high power polycrystalline Er:YAG ceramic laser in-band pumped by a cladding-pumped Er, Yb fiber laser wavelength
locked at 1532 nm with a volume Bragg grating. Using 1.0 at % Er3+-doped ceramic as the gain medium and an output coupler of 10% transmission, the laser had a threshold pump power of ∼1.5
W and generated 11 W of continuous-wave output at 1645 nm for 23.3 W of incident pump power at 1532 nm, corresponding to a
slope efficiency with respect to incident pump power of 51%. 相似文献
999.
Diode-pumped Pr<Superscript>3+</Superscript>:YAlO<Subscript>3</Subscript>/LBO violet laser at 374 nm
We report a diode-pumped Pr3+:YAlO3 laser emitting at 747 nm. A power of 232 mW at 747 nm has been achieved in continuous-wave operation with a diode emitting
2 W at 448 nm. Furthermore, intracavity second-harmonic generation in continuous-wave mode has also been demonstrated with
a power of 52 mW at 374 nm by using a LBO nonlinear crystal. The fluctuation of the violet output power was better than 2.3%.
The beam quality M
2 value is 2.2. 相似文献
1000.
A simple scheme for a switchable multi-wavelength erbium-doped fiber (EDF) ring laser is investigated by using a single stage
of a Sagnac loop mirror. The multiple lasing outputs are obtained and switched readily by controlling the state of polarization
(SOP). Since the transmission characteristics of the Sagnac loop mirror in terms of peak wavelengths and peak powers strongly
depend on the SOP, the switching performance of the proposed multi-wavelength EDF laser can be effectively obtained. The proposed
multi-wavelength EDF laser has versatile lasing outputs in states of a single-, dual-, triple-, and quadruple-wavelength oscillations.
The multiple outputs are effectively switchable by adjusting the SOP. 相似文献