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841.
Park J Lee G Wolff-Fabris F Koh YY Eom MJ Kim YK Farhan MA Jo YJ Kim C Shim JH Kim JS 《Physical review letters》2011,107(12):126402
We report the observation of highly anisotropic Dirac fermions in a Bi square net of SrMnBi(2), based on a first-principles calculation, angle-resolved photoemission spectroscopy, and quantum oscillations for high-quality single crystals. We found that the Dirac dispersion is generally induced in the (SrBi)(+) layer containing a double-sized Bi square net. In contrast to the commonly observed isotropic Dirac cone, the Dirac cone in SrMnBi(2) is highly anisotropic with a large momentum-dependent disparity of Fermi velocities of ~8. These findings demonstrate that a Bi square net, a common building block of various layered pnictides, provides a new platform that hosts highly anisotropic Dirac fermions. 相似文献
842.
We present a general solution to the long-standing problem of determining the masses of pair-produced, semi-invisibly decaying particles at hadron colliders. We define two new transverse kinematic variables M(CT)(⊥) and M(CT)(∥), which are suitable one-dimensional projections of the contransverse mass M(CT). We derive analytical formulas for the boundaries of the kinematically allowed regions in the (M(CT)(⊥),M(CT)(∥)) and (M(CT)(⊥),M(CT)) parameter planes and introduce suitable variables D(CT)(∥) and D(CT) to measure the distance to those boundaries on an event per event basis. We show that the masses can be reliably extracted from the end-point measurements of M(CT)(⊥)(max) and D(CT)(min) (or D(CT)(∥)(min)). We illustrate our method with dilepton tt events at the LHC. 相似文献
843.
We present a string theory construction of a gravity dual of a spatially modulated phase. Our earlier work shows that the Chern-Simons term in the five-dimensional Maxwell theory destabilizes the Reissner-Nordstr?m black holes in anti-de Sitter space if the Chern-Simons coupling is sufficiently high. In this Letter, we show that a similar instability is realized on the world volume of 8-branes in the Sakai-Sugimoto model in the quark-gluon plasma phase. Our result suggests a new spatially modulated phase in quark-gluon plasma when the baryon density is above 0.8Nf fm(-3) at temperature 150 MeV. 相似文献
844.
Wook Jae Yoo Kyoung Won Jang Jeong Ki Seo Ji Yeon Heo Jin Soo Moon Jae Hoon Jun Jang-Yeon Park Bongsoo Lee 《Optical Review》2011,18(1):132-138
In this study, two types of nasal-cavity-attached fiber-optic respiration sensors have been fabricated for noninvasive respiratory
monitoring. One is a silver halide optical-fiber-based respiration sensor that can measure the variations of infrared radiation
generated by the respiratory airflow from a nasal cavity. The other is a thermochromic-pigment-based fiber-optic respiration
sensor that can measure the intensity of reflected light which changes owing to color variations of the temperature-sensing
film according to the temperature difference between inspiratory and expiratory air. We have demonstrated the similarities
of the respiratory signals using the fiber-optic respiration sensors and the temperature transducer of the BIOPAC? system.
In addition, we verified that respiratory signals without the deterioration of the MR image can be obtained using the fiber-optic
respiration sensors. It is anticipated that the proposed noninvasive fiberoptic respiration sensors will be highly effective
for respiratory monitoring of a patient during MRI procedures. 相似文献
845.
846.
Margriet V. D. Z. Park Iseult Lynch Sonia Ram��rez-Garc��a Kenneth A. Dawson Liset de la Fonteyne Eric Gremmer Wout Slob Jacob J. Bried�� Andreas Elsaesser C. Vyvyan Howard Henk van Loveren Wim H. de Jong 《Journal of nanoparticle research》2011,13(12):6775-6787
The biological response to four well-characterized amorphous silica nanoparticles was investigated in RAW 264.7 macrophages in view of their potential application as drug carriers to sites of inflammation. All silica nanoparticles-induced cell membrane damage, reduced metabolic activity, generated ROS and released various cytokines, but to different extents. Two silica nanoparticles of 34 nm (A and B) with different zetapotentials were more cytotoxic than (aggregated) 11 and 248 nm nanoparticles, while cytokines were mostly induced by the (aggregated) 11 nm and only one of the 34 nm nanoparticles (34A). The results indicate that specific silica nanoparticles may have counterproductive effects, for example when used as carriers of anti-inflammatory drugs. The physicochemical properties determining the response of nanoparticles vary for different responses, implying that a screening approach for the safe development of nanoparticles needs to consider the role of combinations of (dynamic) physicochemical properties and needs to include multiple toxicity endpoints. 相似文献
847.
Jiwoon Yeom Jisoo Hong Jae-Hyun Jung Keehoon Hong Jae-Hyeung Park Byoungho Lee 《中国光学快报(英文版)》2011,(12):35-38
We introduce a phase-only hologram generation method based on an integral imaging,and propose an enhancement method in representable depth interval.The computational integral imaging reconstruction method is modified based on optical flow to obtain depth-slice images for the focused objects only.A phaseonly hologram for multiple plane images is generated using the iterative Fresnel transform algorithm.In addition,a division method in hologram plane is proposed for enhancement in the representable minimum depth interval. 相似文献
848.
Objectives
The present study was performed to examine which factors among self-rated scales, perceptual evaluations, and acoustic parameters, calculated from sustained vowels, are reliable indicators of physical and mental fatigues.Methods
A total of 73 volunteers (male:female, 52:21), aged 19–24 years, were enrolled in this study. We defined the high- and low-fatigue groups using the Chalder Fatigue Scale score. For assessment of self-rated symptoms, each subject was asked to complete Voice Handicap Index (VHI) and Voice Rating Scale (VRS). For perceptual evaluations, three clinicians assessed each subject’s vocal quality on the Grade, Roughness, Breathiness, Asthenia, Strain Scale. For acoustic analysis, each subject was asked to produce sustained vowels /a/, /e/, /i/, /o/, and /u/ for 3 seconds. Then, the habitual fundamental frequency (F0), jitter, shimmer, F0 tremor, mean F0, standard deviation of F0, maximum F0, minimum F0, normalized noise energy, harmonic-to-noise ratio (HNR), signal-to-noise ratio (SNR), amplitude tremor, and ratio within 2–4 kHz were calculated using Dr. Speech software.Results
In men, VHI, VRS, F0 tremor, shimmer, HNR, SNR, and amplitude tremor were related to mental fatigue. In women, only VHI was related to physical fatigue, and none of the acoustic parameters was related to the fatigue score. Perceptual evaluations were not related to fatigue in men or women.Conclusions
These findings suggest that self-rated symptoms and acoustic parameters related to voice quality are indicative of mental fatigue, and these features are prominent in men. 相似文献849.
Hyun-Seo Park 《Thermophysics and Aeromechanics》2011,18(2):313-321
The paper presents the investigation of plasma melting of the mixed bottom and fly incineration ash at various mixing ratios
of the components. Chemical compound of the bottom and fly ash as well as the slag after its melting was analyzed by different
methods, and the content of toxic components in them was determined. It is demonstrated that the direct disposal of the fly
and bottom incineration ash may cause dioxin and heavy metal contamination of the environment. The influence of melted ash
basicity on the resulting slag compound was studied. The mass balance of the melting process was defined. The tests were performed
to determine the heavy-metals leaching from the ash and slag. It is also shown that the slag after plasma melting is dioxin-free
and environmentally friendly. 相似文献
850.
I.-H. Bae H. S. Moon S. Zaske C. Becher S. K. Kim S.-N. Park D.-H. Lee 《Applied physics. B, Lasers and optics》2011,103(2):311-319
We present a 532 nm-pumped singly-resonant cw optical parametric oscillator based on MgO-doped PPLN with a minimum threshold
pump power of 0.3 W. The OPO with a two-mirror standing-wave cavity is optimized by using a tunable diode laser on the path
of the resonant signal beam. The maximum output power is 200 mW at an idler wavelength near 1330 nm at a pump power of 2 W.
We report the degradation of the output power and beam characteristics at high pump power indicating a strong thermal lensing
in the crystal. The continuous tuning range of the OPO is measured to be 800 MHz which is close to 90% of the free spectral
range of the OPO cavity. 相似文献