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491.
Self-similar propagation of linearly chirped hyperbolic-secant pulses in a comblike decreasing-dispersion fiber amplifier has been observed experimentally for the first time to our knowledge. The scheme takes advantage of an exact solution of the generalized nonlinear Schr?dinger equation with distributed coefficients. 相似文献
492.
A method of window exchange umbrella sampling molecular dynamics simulation is employed for transmembrane helix assembly. An analytical expression for the average acceptance probability between neighboring windows is derived and combined with the first passage time optimization method to predetermine a parameter set in an optimal range. With the parameter set, the method provides a substantially more efficient sampling of helix-helix interfaces together with the potential of mean force along the helix-helix distance of a transmembrane helix-dimer model, compared to the umbrella sampling method. 相似文献
493.
Phosphor-in-glass (PiG) typed robust color converters were fabricated using Pb-free silicate glasses for high-power white LED applications. SiO2-B2O3-RO(R=Ba,Zn) glass powder showed good sintering behavior and high visible transparency under the sintering condition of 750?°C for 30?min without noticeable interaction with phosphors. By simply changing the thickness of the PiG plate or mixing ratio of glass to Y3Al5O12:Ce3+ phosphor, CIE chromaticity coordinates of the LED can be easily controlled. Enhanced thermal quenching property of PiG compared to phosphor with conventional silicone resin suggests its prominent feasibility for high-power/high-brightness white LEDs. 相似文献
494.
Bo-Hae Im 《Transactions of the American Mathematical Society》2007,359(12):6143-6154
Let be an elliptic curve defined over of conductor and let be the absolute Galois group of an algebraic closure of . For an automorphism , we let be the fixed subfield of under . We prove that for every , the Mordell-Weil group of over the maximal Galois extension of contained in has infinite rank, so the rank of is infinite. Our approach uses the modularity of and a collection of algebraic points on - the so-called Heegner points - arising from the theory of complex multiplication. In particular, we show that for some integer and for a prime prime to , the rank of over all the ring class fields of a conductor of the form is unbounded, as goes to infinity.
495.
Jang DM Myung Y Im HS Seo YS Cho YJ Lee CW Park J Jee AY Lee M 《Chemical communications (Cambridge, England)》2012,48(5):696-698
Detonated nanodiamonds (NDs) exhibit remarkable photocatalytic activity towards the hydrogen gas generation upon 532 nm laser pulse irradiation. Hydrogenation dramatically increases the quantum yield, suggesting that hydrogen-terminated sites work as electron reservoirs. NDs can also be used as effective photocatalysts to reduce graphene oxide. The resulting composites exhibit high and stable photocurrent generation upon visible light irradiation. 相似文献
496.
In this paper, we observed and experimentally investigated a high-performance single- and dual-wavelength erbium-doped fiber
ring laser based on a Sagnac filter which contains a section of high-birefringence photonic crystal fiber (HB-PCF) and a polarization
controller. Incorporation of the high-birefringence photonic crystal fiber can suppress multimode oscillation, improve power
stability and increase the optical signal-to-noise ratio (SNR). Wavelength tunable was achieved by using a polarization controller
in the Sagnac filter. Highly stable single-, dual-wavelength oscillations are tunable within a wavelength range from 1550
to 1562 nm and SNR as high as 57 dB with narrow line width about 0.011 nm, is experimentally demonstrated. 相似文献
497.
Kim YJ Lee HS Im JP Min BH Kim HD Jeong JB Yoon JH Kim CY Kim MS Kim JY Jung JH Kim LH Park BL Shin HD 《Experimental & molecular medicine》2003,35(3):196-202
Transforming growth factor-beta1 (TGF-beta1) can act as both a tumor suppressor and a stimulator of tumor progression. We have examined the relationship between polymorphisms of the TGF-beta1 gene and the risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B virus (HBV) infection. A total of 1,237 Korean subjects were prospectively enrolled; 1,046 patients with chronic HBV infection and 191 healthy controls with no evidence of recent or remote HBV infection. The patients were divided into two groups: those without (n = 809) and those with HCC (n = 237). Single nucleotide polymorphisms (SNPs) of TGF-beta1 were searched for and genotyped using the single base extension method. In Korean subjects, only two SNPs were found among the seven known polymorphisms of TGF-beta1, at position -509 and in codon 10. The risk of HCC was significantly lower in patients with the T/T or C/T genotypes than in those with the C/C genotypes at position -509 (P < 0.02), and also lower among those with the Pro/Pro or Leu/Pro genotypes than in those with the Leu/Leu genotypes in codon 10 (P < 0.007). Haplotype analysis revealed that the possession of [-509C > T; L10P] conferred a decreased likelihood of HCC (OR = 0.74; 95% CI, 0.59-0.93; P = 0.008). In conclusion, the presence of the TGF-beta1 -509C > T promoter or of the L10P polymorphism, and the combination of both [-509C > T; L10P] as a haplotype were strongly associated with a reduced risk of HCC in patients with chronic HBV infection. 相似文献
498.
Byeong Su Gu Dr. Soumen Dutta Yu-Rim Hong Dr. Odongo Francis Ngome Okello Hyeonae Im Seungil Ahn Prof. Dr. Si-Young Choi Prof. Dr. Jeong Woo Han Prof. Dr. Sunmin Ryu Prof. Dr. In Su Lee 《Angewandte Chemie (International ed. in English)》2023,62(31):e202307816
The performance of nanocrystal (NC) catalysts could be maximized by introducing rationally designed heterointerfaces formed by the facet- and spatio-specific modification with other materials of desired size and thickness. However, such heterointerfaces are limited in scope and synthetically challenging. Herein, we applied a wet chemistry method to tunably deposit Pd and Ni on the available surfaces of porous 2D−Pt nanodendrites (NDs). Using 2D silica nanoreactors to house the 2D-PtND, an 0.5-nm-thick epitaxial Pd or Ni layer ( e - Pd or e -Ni ) was exclusively formed on the flat {110} surface of 2D−Pt, while a non-epitaxial Pd or Ni layer ( n - Pd or n -Ni ) was typically deposited at the {111/100} edge in absence of nanoreactor. Notably, these differently located Pd/Pt and Ni/Pt heterointerfaces experienced distinct electronic effect to influence unequally in electrocatalytic synergy for hydrogen evolution reaction (HER). For instance, an enhanced H2 generation on the Pt{110} facet with 2D-2D interfaced e -Pd deposition and faster water dissociation on the edge-located n -Ni overpowered their facet-located counterparts in respective HER catalysis. Therefore, a feasible assembling of the valuable heterointerfaces in the optimal 2D n -Ni/e-Pd/Pt catalyst overcame the sluggish alkaline HER kinetics, with a catalytic activity 7.9 times higher than that of commercial Pt/C. 相似文献
499.
500.
Gregory F. Meyers Michael T. Dineen Edward O. Shaffer II Ted Stokich Jr. Jang‐hi Im 《Macromolecular Symposia》2001,167(1):213-226
Scanning probe microscopy (SPM) techniques are used to characterize surfaces related to the processing of benzocyclobutene (BCB) dielectric thin films. Thermally cured resins and photodefineable resins are sold under the trade name CYLCOTENETM1) for electronic applications. TappingMode AFM (TMAFM) imaging is used to follow changes in adhesion promoter morphology upon baking to help explain adhesion performance. Power spectral density (PSD) analysis of TMAFM images of plasma treated BCB surfaces are unique and can be used to ‘fingerprint’ processes. Selective oxidation of the BCB surface can be used to fabricate a phase imaging standard for TMAFM. Near surface modulus of the BCB materials is 3.6 ± 0.2 GPa and the hardness is 0.38 ± 0.2 GPa measured by depth‐sensing nanoindentation. Creep recovery of indents can be used to qualitatively distinguish between thermal and photocureable materials. A heated tip in a scanning thermal microscope can induce the thermal curing of BCB over micron sized areas. Local thermal analysis with the same probe allows the measurement of the changes in the glass transition, Tg, at the surface with cure temperature. 相似文献