نتایج جستجو برای: diamond
تعداد نتایج: 20974 فیلتر نتایج به سال:
A novel simple and versatile synthetic strategy is developed for the surface modification of boron-doped diamond. In a two-step procedure, polyethyleneimine is adsorbed on the hydrogenated diamond surface and subsequently modified with a model light-harvesting donor-π-bridge-acceptor molecule (coded P1). The sensitized diamond exhibits stable cathodic photocurrents under visible-light illuminat...
Donor-acceptor type light-harvesting molecular wires are covalently attached to a borondoped diamond surface via a combination of diazonium electrografting and Suzuki crosscoupling. For the Suzuki reaction, various catalytic systems are compared with respect to their imposed surface coverage. Combining 2-dicyclohexylphosphino-2’,6’-dimethoxybiphenyl (SPhos) and Pd(0), the diamond coverage impro...
The new diamond-like B-C phase was obtained from the graphite-like BC phase in a laser-heated diamond anvil cell at high temperature 2230+/-140 K and high pressure 45 GPa. Raman spectra of the new phase measured at ambient conditions revealed a peak at 1315 cm(-1), which was attributed to longitudinal-optical (LO) mode. The X-Y Raman mapping was used to investigate spatial distribution of the d...
In this work, we study the modification of hydrogenated diamond films deposited on silicon resulting from its exposure to DBr followed by an annealing above 600 K, using high resolution electron energy loss spectroscopy (HREELS). This procedure results in silicon carbide SiC formation within the diamond film, as evidenced by the observation of a loss peak at 117 meV and its first harmonic at 23...
The performance ofaluminum gallium nitride/gallium nitride (AlGaN/GaN) high-electron-mobility transistors (HEMTS) diamond and silicon carbide (SiC) substrates is examined. Additionally, the temperature rise in similar devices on diamond and SiC substrates is reported. Recently, identical AlGaN/GaN HEMTs have been fabricated at Cornell NanoScale Science & Technology Facility (CNF) on diamond, bu...
Ion-beam bombardment/rnilling was used for sharpening of diamond particles deposited on ends of silicon tips. Radii curvature of diamond coating down to about 20 nm have been formed in such a way. Field emission experiments with sharpened diamond coated emitters have shown that the ion beam treatment effects a considerable shift of current-voltage characteristics of in the lower voltage region.
We show that the top of any diamond with bottom 0 in the r.e. degrees is also the top of a stack of n diamonds with bottom 0. Let R be the upper semilattice of the recursively enumerable degrees. A minimal pair consists of two incomparable r.e. degrees with innmum equal to the recursive degree 0. An r.e. degree is cappable if it is one half of a minimal pair. An r.e. degree a is the top of a di...
The photoemission properties of thin diamond and fullerene films were investigated for advanced accelerator applications, using subpicosecond laser pulses at three different wavelengths (650, 325, and 217 nm). The quantum efficiency (QE) obtained at 217 nm with a boron-doped, p-type, (111) polycrystalline diamond film (2.6 lop4) was only five times smaller than the QE obtained with a mirror pol...
Diamond-coated steel is considered an important issue in synthetic diamond technology due to the great economical importance of enhancing the wear resistance and surface hardness of commercial Fe-based alloys. However, direct diamond coating by chemical vapour deposition (CVD) is rather problematic—adhesion and growth are seriously affected. The use of interlayers is a common approach to minimi...
The National Cancer Institute Inherited Bone Marrow Failure Syndromes Cohort enrolls patients with the four major syndromes: Fanconi anemia, dyskeratosis congenita, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome, and follows them with a common comprehensive protocol. The current analysis includes more than double the numbers of patients and person-years since our first report, publishe...
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