Dynamics of ultra-intense circularly polarized solitons under inhomogeneous plasmas

The dynamics of the ultra-intense circularly polarized solitons under inhomogeneous plasmas are examined. The interaction is modeled by the Maxwell and relativistic hydrodynamic equations and is solved with fully implicit energy-conserving numerical scheme. It is shown that a propagating weak soliton can be decreased and reflected by increasing plasma background, which is consistent with the existing studies based on hypothesis of weak density response. However it is found that ultra-intense soliton is well trapped and kept still when encountering increasing background. Probably, this founding can be applied for trapping and amplifying high-intensity laser-fields.Comment: 4 pages, 3 figures, submitted to Phys. Plasma

Acoustic comfort in large railway stations

Large railway stations attract a wide range of passengers and citizens, and these buildings are likely to have a complex acoustic environment. Previous studies have focused on reducing people’s exposure to excessive sound levels caused by transportation, but more research is needed to assess people’s preferences and ensure their psychophysical wellbeing. The aim of this study was to explore the complex aspects of the sound environment in large railway stations that contribute to acoustic comfort. On-site measurements and an acoustic comfort survey were performed at a case study site in Harbin, China. The results showed a significant positive correlation between the subjective comfort evaluations and objective measurements of the sound pressure level and reverberation time. Differences in dominant sound sources in different spaces lead to different evaluations of acoustic comfort. People prefer broadcast sound, but its intelligibility needs to be improved. When the density of people increases, the preference for speech sounds and activity sounds decline rapidly. With regard to demographic and social factors, older people and people with higher incomes and education levels are more tolerant of the environment. As railway transportation has become modernized, large railway stations now play an important role in civic architecture. The aim of this study was to explore the effects of sound sources on the sound environment and acoustic comfort in such an extra-large space. Based on subjective and objective measurements of a typical railway station in China that has an extra-large space and multiple sound sources, the effects of sound sources in different functional zones were studied. The overall acoustic comfort and sound pressure levels were related to the sonic composition of the sound sources. The roles of various individual sound sources were investigated, including the speech sounds of other passengers in the seating area, the speech sounds of staff, the sounds of placing luggage in the security scan machine in the security check area, the sounds of a ticket machine in the ticket lobby, and the speech sounds of restaurant workers. The sound sources that have dominant impacts on the survey participants' evaluations of acoustic comfort were determined. In terms of acoustic comfort, broadcast sound was the most preferable, whereas mechanical noise and luggage noise were the least preferable. The sound levels of speech, the intelligibility of both broadcast and speech sounds, and the loudness of the three dominant sound sources exhibited a linear correlation with the sound pressure level. In terms of the effect of the sound characteristics on acoustic comfort, the sound level of speech was the dominant factor. Overall, acoustic comfort can be effectively improved by better planning of the combination and arrangement of sound sources

Highly Stable Luminous "snakes" from CsPbX3 Perovskite Nanocrystals Anchored on Amine-Coated Silica Nanowires

CsPbX3 (X = Cl, Br, and I) perovskite nanocrystals (NCs) are known for their exceptional optoelectronic properties, yet the material's instability toward polar solvents, heat, or UV irradiation greatly limits its further applications. Herein, an efficient in situ growing strategy has been developed to give highly stable perovskite NC composites (abbreviated CsPbX3@CA-SiO2) by anchoring CsPbX3 NCs onto silica nanowires (NWs), which effectively depresses the optical degradation of their photoluminescence (PL) and enhances stability. The preparation of surface-functionalized serpentine silica NWs is realized by a sol-gel process involving hydrolysis of a mixture of tetraethyl orthosilicate (TEOS), 3-aminopropyltriethoxysilane (APTES), and trimethoxy(octadecyl)silane (TMODS) in a water/oil emulsion. The serpentine NWs are formed via an anisotropic growth with lengths up to 8 μm. The free amino groups are employed as surface ligands for growing perovskite NCs, yielding distributed monodisperse NCs (∼8 nm) around the NW matrix. The emission wavelength is tunable by simple variation of the halide compositions (CsPbX3, X = Cl, Br, or I), and the composites demonstrate a high photoluminescence quantum yield (PLQY 32-69%). Additionally, we have demonstrated the composites CsPbX3@CA-SiO2 can be self-woven to form a porous 3D hierarchical NWs membrane, giving rise to a superhydrophobic surface with hierarchical micro/nano structural features. The resulting composites exhibit high stability toward water, heat, and UV irradiation. This work elucidates an effective strategy to incorporate perovskite nanocrystals onto functional matrices as multifunctional stable light sources

WAITER : a wearable personal healthcare and emergency aid system

2007-2008 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

Volatile components of fruits of Ligustrum lucidum Ait. stimulate proliferation and differentiation of rat calvarial osteoblasts

The fruits of Ligustrum lucidum Ait., (FLL), which contain rich volatile components, are commonly used as tonic for kidney and liver in the  traditional Chinese medicine prescriptions. This study aimed to investigate the effects of volatile components of FLL on the proliferation and   differentiation of rat calvarial osteoblasts by the MTT method and  measuring the activity of alkaline phosphatase (ALP). Results showed that volatile components (1 to 100 μg/mL) of FLL significantly (p<0.01) stimulated the proliferation and increased the ALP activity of rat calvarial osteoblasts which indicated that volatile components of FLL played an important role in osteoblastic bone formation just as non-volatile  components in FLL. Such finding accredited the FLL as a potential  candidate that might be useful in bone engineering and in treating bone defects including osteoporosis. The volatile components were analyzed by GC-MS. A total of 67 compounds were identified and the main components included (Z,Z)- 9,12-octadecadienoic acid (33.47%), n-hexadecanoic acid (15.02%), (E)-9-octadecenoic acid (9.03%), α-cadinol (6.51%), 4-hexyl-2,5-dihydro-2,5-dioxo-3-furanacetic acid (4.93%) and (E)-8-octadecenoic acid methyl ester (2.69%).Key words: Ligustrum lucidum, volatile components, rat calvarial osteoblasts